A device case includes a case body (1) having a side wall (1a) and an opening, a lid plate (2) for closing the opening, an end portion of the lid plate projecting from an outer surface of the side wall, and a welded portion (MP) that joins the lid plate (2) with the side wall (1a). The lid plate (2) has a beam receiving area located in a vicinity of an end portion of the lid plate for receiving a beam emitted vertically with respect to the beam receiving area.