A pivot member includes: a first member configured to pivot about a pivot axis; and a second member having a connecting surface, at least a portion of which has a flat surface. The second member is disposed such that the flat surface and the first member are opposed to each other. The second member has at least one surface different from the flat surface. A first identifier and a second identifier are provided on the at least one surface. The first identifier is visually recognizable from a first direction orthogonal to the flat surface. The second identifier is visually recognizable from the first direction and from a second direction in which the first identifier is not visually recognizable.

A pivot member includes: a first member configured to pivot about a pivot axis; and a second member having a connecting surface, at least a portion of which has a flat surface. The second member is disposed such that the flat surface and the first member are opposed to each other. The second member has at least one surface different from the flat surface. A first identifier and a second identifier are provided on the at least one surface. The first identifier is visually recognizable from a first direction orthogonal to the flat surface. The second identifier is visually recognizable from the first direction and from a second direction in which the first identifier is not visually recognizable.

A pivot member includes: a first member configured to pivot about a pivot axis; and a second member having a connecting surface, at least a portion of which has a flat surface. The second member is disposed such that the flat surface and the first member are opposed to each other. The second member has at least one surface different from the flat surface. A first identifier and a second identifier are provided on the at least one surface. The first identifier is visually recognizable from a first direction orthogonal to the flat surface. The second identifier is visually recognizable from the first direction and from a second direction in which the first identifier is not visually recognizable.

A pivot member includes: a first member configured to pivot about a pivot axis; and a second member having a connecting surface, at least a portion of which has a flat surface. The second member is disposed such that the flat surface and the first member are opposed to each other. The second member has at least one surface different from the flat surface. A first identifier and a second identifier are provided on the at least one surface. The first identifier is visually recognizable from a first direction orthogonal to the flat surface. The second identifier is visually recognizable from the first direction and from a second direction in which the first identifier is not visually recognizable.