A casing angle adjustment mechanism capable of adjusting the angle of a casing with respect to a mounting surface by a simple operation of a leg unit is provided. When an angle adjustment mechanism of a casing rotates a leg unit in one direction, moves a part of a stopper along a connection hole of the leg unit, and slides a slide plate, a side wall of the slide plate blocks openings of engagement holes of the leg unit, and a side wall of the leg unit blocks openings of engagement grooves of the slide plate, and when it rotates the leg unit in another direction, moves the part of the stopper along the connection hole of the leg unit, and slides the slide plate, engagement grooves of the slide plate and engagement holes of the leg unit are placed to overlap.