A traveling car includes a car body and a driver. The driver has a motor that is attached to the car body, a drive wheel, a support that supports the drive wheel, and a transmission that transmits rotary drive force to the drive wheel. The support has a holder that rotatably supports the drive wheel and is attached to the car body so as to rotate about a rotation axis M extending in the horizontal direction. The transmission has an output pulley that is coupled to the motor and is located on the car body, an input pulley that is coupled to the drive wheel and is located on the holder, and a belt wound around the output pulley and the input pulley. The rotation axis M is located coaxial with the output pulley.

Provided is a linear motion mechanism having a further enhanced strength of a structure. The linear motion mechanism including an intermediate link including a conversion mechanism that converts a rotational force from a motor into a driving force in a linear direction, the intermediate link extending in the linear direction, a first link that linearly moves toward a first side in the linear direction from an end of the intermediate link on the first side on the basis of the driving force in the linear direction, and a second link that linearly moves toward a second side opposite to the first side from an end of the intermediate link on the second side on the basis of the driving force in the linear direction, in which the first link and the second link linearly move symmetrically in the linear direction in conjunction with each other.

Provided is a linear motion mechanism having a further enhanced strength of a structure. The linear motion mechanism including an intermediate link including a conversion mechanism that converts a rotational force from a motor into a driving force in a linear direction, the intermediate link extending in the linear direction, a first link that linearly moves toward a first side in the linear direction from an end of the intermediate link on the first side on the basis of the driving force in the linear direction, and a second link that linearly moves toward a second side opposite to the first side from an end of the intermediate link on the second side on the basis of the driving force in the linear direction, in which the first link and the second link linearly move symmetrically in the linear direction in conjunction with each other.