An electronic device and hinge assembly includes an electronic device body including a base and a main unit, and hinge devices pivotally connecting the base and the main unit for allowing adjustment of the angular position of the main unit relative to the base step by step in a series of angles. Each hinge device includes a casing affixed to one of the base and the main unit, a pivot shaft connected to the base and the main unit and rotatably inserted through the casing and secured by a retaining ring, and a friction wheel set and a damper mounted on the pivot shaft. The friction wheel set includes a first friction wheel and having recessed portions equiangularly spaced at one side thereof, and a second friction wheel rotatable with the pivot shaft relative to the first friction wheel and having raised portions respectively engageable into the recessed portions.