To solve such a problem that a nut itself tilts some time when the nut is pressed in or a large deflection or crack is brought in the resin case is some case, although a structure fixing the resin case to a bracket by pressing nuts in press-in holes of the resin case and inserting a bolt and screwing it into the hole has been usually used in the conventional mounting structure for a resin case.

In the mounting structure of a resin case, a face kept into contact with a bracket of a press-in nut is formed in a first convex face and a face kept in contact with the bracket of a bolt is formed in a second convex face. The first convex face and the second convex face are brought into contact with each other at the inner peripheral section of the penetration hole to hold the bracket, and fix the resin case to the bracket.