In a camera to which the present invention is applied, a camera body having a pop-up ST unit attached thereto is sandwiched between front and back covers. A plugged rubber arranged inside the back cover is pressed by a front cover rib provided on the front cover in the state in which the front and back covers are joined to each other, whereby the front and back covers are kept liquid-tight to each other. Moreover, an ST rubber arranged on the periphery of the ST body is pressed by the front cover rib in the state in which the ST body is sandwiched between the front and back covers, whereby the front cover, the back cover, and the ST body are kept liquid-tight to one another. Simultaneously, the ST rubber is pressed by a cover rib provided on the back cover, whereby the back cover and the ST body are kept liquid-tight to each other. Thus, the water-proofing function can be secured among the three members, that is, the front cover, the back cover, and the ST body.