A connector includes: an outer housing that includes an inserting part having a tubular shape, and is fixed to a first surface of a wall part in a state in which the inserting part is inserted into a hole part of the wall part; and an inner housing including a main body that is inserted into the hole part from a second surface side to be engaged with the outer housing, and a projecting part projecting from the main body. The projecting part projects from the main body toward a rear side in an insertion direction with respect to the hole part, and is configured such that a rear end surface of the projecting part is located to be flush with the second surface when the main body is completely engaged with the outer housing.