An optical communication unit performs a bidirectional information transmission between a circuit device in a fixed housing and a circuit device in a moving housing with an optical signal. The optical communication unit includes a light transmitting unit that transmits the optical signal, a light receiving unit that receives the optical signal from the light transmitting unit, and a light propagation path for propagating the optical signal from the light transmitting unit to the light receiving unit. The light propagation path is disposed inside a hinge part that links the fixed housing and the moving housing in an openable and closable manner.