The invention relates to a dual mode type grinder which comprises a base. A left hanging frame, a motor and a right hanging frame are sequentially installed on the base from left to right. The motor is connected with a transmission gear, the transmission gear is meshed with a driving gear, the driving gear is connected with a spindle which is installed on the base through a bearing, a left belt pulley is installed at the middle of on the spindle, the right side of the left belt pulley is provided with a right belt pulley, and a rear belt pulley is arranged at the back of an area between the left belt pulley and the right belt pulley. A belt enabling the left belt pulley, the right belt pulley and the rear belt pulley to be in transmission connection is arranged between the left belt pulley, the right belt pulley and the rear belt pulley. The dual mode type grinder is high in automation degree, not only can achieve an automatic grinding function, but also can effectively control a grinding wheel to perform left-right reciprocating sliding through the sliding of a draw key and control over rotation of an eccentric wheel, and an effect of conveniently grinding and processing a long and narrow plane on a workpiece is achieved.