Patent ID: 8794824

Claim:
A case unit comprising: a resin case main body which includes an outer peripheral surface, and an opening forming surface enclosed by the outer peripheral surface and being formed with an opening; a step which is provided on an inner peripheral surface of the opening of the resin case main body and which faces an entrance of the opening; an elastic member which is provided along the inner peripheral surface of the opening of the resin case main body and which is mounted on the step; a light transmission member which includes an outer periphery, which is press-fitted in the opening of the resin case main body with the elastic member being interposed between the outer periphery of the light transmission, member and the inner peripheral surface of the opening of the resin case main body, and which covers the opening; and a frame member which includes a fitting part fitted on the outer peripheral surface of the resin case main body and an elastic member pressing part extending from the fitting part towards the entrance of the opening of the resin case main body and covering at least a part of the elastic member at the entrance of the opening, wherein the fitting of the fitting part of the frame member on the outer peripheral surface of the resin case main body is performed by press fit.