A connector fitting structure, between a first connector and a second connector that are fitted and electrically connected to each other, is provided. The first connector includes a first housing that accommodates a first connection terminal. The second connector includes a second housing that accommodates a second connection terminal, and an abutment portion that is provided on a portion of the second housing and against which the first housing abuts before the first connector is fitted into the second connector. The abutment portion includes a concave portion and a convex portion, A front end of the convex portion is configured to be an abutment surface.