To realize a rotating mechanism by which a bearing section is stably rotated relative to a shaft section. A rotating mechanism includes a shaft section having a groove, and a bearing section which is provided with an opening for supporting the shaft section, has a shielding plate shielding part of the opening and disposed inside the groove, and is rotated around a rotational axis. The shielding plate may shield a region containing the rotational axis, and may have a projecting portion projecting from the shielding plate toward the inside of the groove, between the shielding plate and the groove.

A sensor includes: an upper electrode; a lower electrode provided facing the upper electrode; an upper electrode support portion provided in an upper portion of the upper electrode; a deforming portion provided at both ends of the upper electrode support portion and enabling a distance between the upper electrode and the lower electrode to be changed; a rotatable actuator arranged facing the upper electrode support portion; and a member arranged between the upper electrode support portion and the actuator, and capable of moving relative to at least one of the actuator and the upper electrode support portion when the actuator presses the upper electrode support portion.

A sensor includes: an upper electrode; a lower electrode provided facing the upper electrode; an upper electrode support portion provided in an upper portion of the upper electrode; a deforming portion provided at both ends of the upper electrode support portion and enabling a distance between the upper electrode and the lower electrode to be changed; a rotatable actuator arranged facing the upper electrode support portion; and a member arranged between the upper electrode support portion and the actuator, and capable of moving relative to at least one of the actuator and the upper electrode support portion when the actuator presses the upper electrode support portion.

A relationship of 0<.sub.1<2.sub.1 is satisfied, where .sub.1 is an angle formed between a first line which is vertical to a parallel line passing through a pivot center point and being parallel to a pivot extending direction, passes through a center point of a first portion from the center point of the first portion toward the parallel line, and a second line which is vertical, at the center point of the first portion, to a first portion extending direction, passes through the center point of the first portion toward a vertical line being vertical to the parallel line and passing through the pivot center point, and where .sub.1 is an angle formed between the first line and a third line connecting the pivot center point and the center point of the first portion from the center point of the first portion toward the pivot center point.

A relationship of 0<.sub.1<2.sub.1 is satisfied, where .sub.1 is an angle formed between a first line which is vertical to a parallel line passing through a pivot center point and being parallel to a pivot extending direction, passes through a center point of a first portion from the center point of the first portion toward the parallel line, and a second line which is vertical, at the center point of the first portion, to a first portion extending direction, passes through the center point of the first portion toward a vertical line being vertical to the parallel line and passing through the pivot center point, and where .sub.1 is an angle formed between the first line and a third line connecting the pivot center point and the center point of the first portion from the center point of the first portion toward the pivot center point.

To realize a rotating mechanism by which a bearing section is stably rotated relative to a shaft section. A rotating mechanism includes a shaft section having a groove, and a bearing section which is provided with an opening for supporting the shaft section, has a shielding plate shielding part of the opening and disposed inside the groove, and is rotated around a rotational axis. The shielding plate may shield a region containing the rotational axis, and may have a projecting portion projecting from the shielding plate toward the inside of the groove, between the shielding plate and the groove.

To realize a rotating mechanism by which a bearing section is stably rotated relative to a shaft section. A rotating mechanism includes a shaft section having a groove, and a bearing section which is provided with an opening for supporting the shaft section, has a shielding plate shielding part of the opening and disposed inside the groove, and is rotated around a rotational axis. The shielding plate may shield a region containing the rotational axis, and may have a projecting portion projecting from the shielding plate toward the inside of the groove, between the shielding plate and the groove.

A keyboard apparatus includes a key; a guide regulating a direction in which the key moves, the guide being arranged at three or more locations not lined in a straight line when seen along a scale direction of the key, and the guide slidably making contact with the key from the scale direction; and a connecting portion connecting the key to a frame at the back side of the key from the guide, the connecting portion including a rod-like flexible member.

A keyboard apparatus includes a key; a guide regulating a direction in which the key moves, the guide being arranged at three or more locations not lined in a straight line when seen along a scale direction of the key, and the guide slidably making contact with the key from the scale direction; and a connecting portion connecting the key to a frame at the back side of the key from the guide, the connecting portion including a rod-like flexible member.

A keyboard apparatus includes: a key disposed so as to be pivotable with respect to a frame; a first member, an elastic member being disposed on at least a portion of a surface of the first member; a second member configured to be moved on the elastic member while elastically deforming the elastic member in response to pivotal movement of the key; and a hammer assembly connected to the key via the first member and the second member so as to pivot in response to pivotal movement of the key.