A hinge device includes a first connecting member, a second connecting member, and a locking member. The first connecting member defines a connecting portion hole therein. A positioning arm with an angled surface is located on the first connecting member. The second connecting member defines a connecting body hole therein. A connecting body post is located on the second connecting member. The locking member engages in the connecting portion hole and the connecting body hole so that the first connecting member is rotatable relative to the second connecting member. The connecting body post abuts on the angled surface and the first connecting member is rotated between a first position where a first friction is generated between the connecting body post and the angled surface, and a second position where a second friction is generated between the connecting body post and the angled surface and greater than the first friction.