To provide a mounting structure for an opening and shutting lid, which effectively prevents the rattle of the opening and shutting lid used to open and shut the operating face of an electronic apparatus and which improves the sensation of operating, and to provide a support shaft structure used for the mounting structure and to provide an opening-and-shutting lid structure.

A front case 10 having an operating face 10a is provided. A thin sheet-like opening and shutting lid 20 which is shaft-supported rotatably by a cam arm 22, and a shaft arm 23 extended to one end of the front case 10 and which opens and shuts the operating face 10a is installed. A cam member 12 which shaft-supports the cam arm 22 at the opening and shutting lid 20, which is fixed to the front face 10 and which urges the opening and shutting operation of the opening and shutting lid 20, is provided. In addition, a shaft member 13, which is fixed by a spacer 14 fitted to the front case 10 and which shaft-supports the shaft arm 23, is provided. As a result, protrusion parts are installed at the can arm 22 and the shaft arm 23 at the opening and shutting lid 20, they are brought into contact with the tip of the cam member 12 and the tip of the shaft member 13, and backlash in the opening and shutting lid 20 is prevented.