The present invention is intended to obtain a reflector supporting mechanism capable of preventing axial deviation of a sleeve of a reflector side and a socket of a supporting mechanism side and facilitating remounting of the reflector supporting mechanism from/onto the reflector. The reflector supporting mechanism according to the present invention comprises a cylindrical sleeve, a socket which is provided with a flange and crowned at its tapered side part and adapted to come in contact with the sleeve by a side contact point and a flange part, and a universal joint provided on the socket.