Fitting construction of electrical connection box

Claim 1

A fitting construction of an electrical connection box, comprising: a casing member which is made of resin and includes a first peripheral wall having an upper end, a projection being formed at the upper end of the first peripheral wall; and a cover member which is made of resin and includes a second peripheral wall having a lower face, a downwardly opening fitting groove being formed on the lower face of the second peripheral wall so as to be mounted on an upper portion of the casing member through fitting of the projection into the fitting grove; wherein the fitting grove is shaped so as to become wider towards a lower end of the fitting groove, while the projection is shaped so as to become wider towards a lower end of the projection; a locking member for locking the cover member and the casing member together, the locking member being formed separately from both the projection and the fitting groove; wherein the projection is brought into pressing contact with opposed side faces of the fitting groove at the time of fitting of the projection into the fitting groove so as to spread out the fitting groove and said projection includes a top portion which provides sealing engagement at a point spaced from the peripheral wall of the casing member when said cover member is locked by said locking member to said casing member.