To provide a light conductor coupling capable of transmitting a signal insensitive to disturbance in simple constitution.

This light conductor coupling has first and second coupling members 10, 12, which the coupling members 10, 12 are couplable with one another and in each of which a light conducting element 18 is held. As at least one of the light conducting elements 18 is elastically biased, the two light conducting elements 18, 18 are pressed against one another with their end surfaces 26, 26' and it is made possible to transmit the light from one of the light conducting elements 18, 18 to the other. The end surface 26 of the one light conducting element 18 has a spherical protruded shape, and the end surface 26' of the other light conducting element 18 has a recessed shape of the same radius of curvature as the one.