An exemplary joint mechanism (100) includes a pivot shaft (10), a joint (20), a rotary arm (30), and two bearings (50). The pivot shaft (10) is non-rotatable relative to the joint (20). The joint (20) is received in the rotary arm (30). The rotary arm (30) is rotatable relative to the joint (20). The two bearings (50) are fixed to an inner surface of the rotary arm (30). Each bearing (50) includes a concave inner surface, and the concave inner surface is engaged with a curved outer surface of the joint (20).