A computer with a case member mounting structure includes a first case member, a second case member, a slide, a spring member, and an operation lever. The first case member has at least one opening. The second case member includes at least one first retaining member. The slide is movably supported on the first case member. The push portion of the first retaining member is inserted into the opening for pushing the slide to move in a first direction to a first position so that the hooked portion of the first retaining member is engaged with the opening. The operation lever is pivoted to the first case member. When the operation lever is rotated to a second position, the operation lever pushes the slide to move in the first direction, so as to disengage the hooked portion from the opening.