A lamp socket (20) of the invention mainly includes an upper socket (21), a lower socket (22), and terminal members (23). The upper socket 21 has a bulb mounting portion (25) formed on an upper side of an socket body (24), and a wire connection portion (26) is formed on a side surface of the socket body (24). This wire connection portion (26) has two wire insertion grooves (30, 30) formed by opposite side walls (27, 27), projecting from the socket body (24), and a partition wall (28). The lower socket (22) has a connector housing (35) formed on a lower side of a lower socket body (34), and a terminal receiving plate (36) projects from a side surface of the lower socket body. Terminal setting grooves (37) are formed in this terminal receiving plate (36).