To compactly integrate a push-button in a narrow space.

The thin electronic device includes a rear cover 2 that is fit in the front panel and composed of a back plate 2A and a peripheral frame 2B, wherein the upper plate 2a of the peripheral frame 2B is tiltd aslant toward outside at a predetermined angle of gradient in the direction of the front panel, a button hole 3 is provided through the upper plate 2a, and a synthetic resin push-button 4 is arranged in the button hole 3. The push-button 4 has a button body 4A inserted in the button hole 3 and a pair of elastically displaceable back and forth elastic arms 4E and 4F that extend outward from the peripheral edge of the button body 4A. The playing ends of both the elastic arms 4E and 4F are built in one body via a common substrate 4G. The button body 4A is inserted into the button hole 3 by pressure-fitting each of the lock holes 19a and 19b of the common substrate 4G to the lock pins 21a and 21b protruded from the underside of the upper plate 2a.