An electric stimulator includes a housing, a control circuit board, and at least two electrode plates. The housing includes an internal space formed therein and an outside surface in which at least one electrode plate retention slot is formed. The control circuit board is mounted in the internal space of the housing to control intensity and frequency of a current output. The electrode plates are electrically conductive and are received in the electrode plate retention slot of the housing and are in electric connection with the control circuit board. The electrode plates have an outside surface including a large-area contact surface and a small-area contact surface connected to the large-area contact surface. The large-area contact surface has a surface area greater than that of the small-area contact surface. The large-area contact surface and the small-area contact surface define therebetween an inclined angle that is not equal to 180 degrees.
