The utility model provides an auxiliary electrode cap sharpening machine. According to the auxiliary electrode cap sharpening machine, a clamping and withdrawing mechanism comprises clamping cylinders and a withdrawing cylinder, piston rods of the two clamping cylinders point the left side of a connecting board and the right side of the connecting board respectively, the piston rods of the two clamping cylinders are respectively connected with an electrode cap installation arm and are respectively used for clamping an electrode cap through a corresponding electrode cap clamping arm, a grinding mechanism comprises a grinding support fixed on a supporting base, a sharpening tool bit is fixed on the front lateral side, opposite to the electrode cap installation arms, of the grinding support in a rotary mode, and the axis of the grinding tool bit is parallel to the axis of each electrode cap installation arm. According to the auxiliary electrode cap sharpening machine, the clamping and withdrawing mechanism is simple in structure, convenient to install and maintain, and accurate in electrode cap positioning, the clamping cylinders are used for clamping the electrode cap, the clamping and withdrawing mechanism is accurately matched with the grinding mechanism, therefore, grinding can be achieved more conveniently and fast, and production efficiency is effectively improved.