The invention discloses a cutter fixing device. The cutter fixing device comprises a disc-shaped base, a chute positioned on one end surface of the base, and a cutter fixing slide block slidingly arranged in the chute; a cutter is fixed on the side, far from the base, of the cutter fixing slide block in the center line direction of the base; a driving groove for receiving a driving block is formedin the base below the chute; the driving block is fixedly connected with the cutter fixing slide block; the driving block can slide back and forth in the driving groove in the sliding direction of the cutter fixing slide block; a transmission shaft is arranged on the center line of the base; an inclined tooth inclined relative to the sliding direction of the cutter fixing slide block is arrangedon the side, near the transmission shaft, of the driving block; the transmission shaft is provided with an inclined tooth cooperating with the inclined tooth on the driving block; and the transmissionshaft can perform a reciprocating motion along the axis in a certain range. The cutter fixing device not only can realize rotation of the cutter, but also can synchronously realize change of the rotating diameter of the cutter.