A cover unit to open and close an opening formed in a main body includes a cover including a hinged first end portion, a second end portion including an engagement portion provided on a side facing the opening, and a deformable portion deformable toward the main body, provided in the second end portion, a rotation stopper disposed between the cover and the opening, to inhibit the cover from rotating excessively, and a push latch unit disposed in the main body to lock and unlock the cover, including an engagement pawl to contact the engagement portion of the cover when the rotation stopper prohibits the cover from rotating further to the main body. When the second end portion is pressed while the rotation stopper prohibits the cover from rotating, the engagement portion of the cover is engaged or disengaged from the engagement pawl of the push latch unit.