A power source connector device includes a first connector and a second connector. The first connector includes a first housing and first terminals. The second connector includes second terminals. The second terminals face each other at least partially with a space in between. When the first connector and the second connector fit to each other, a portion of the first housing is disposed in the space. At the same time, a portion of an outer wall of one of the first connector and the second connector abuts an inner wall of the other of the second connector or the first connector. An engaging portion is disposed on the outer wall, and a corresponding engaging portion for engaging with the engaging portion is disposed on the inner wall. The engaging portion is supported using the first housing disposed in the space.