The utility model discloses a threading machine, which comprises a seat (1), an upright column (2), a working stand (3), a motor (4), V belts (5), a power head mounting frame (7), a lubricating oil cup (8), a handle (10) and a drill chuck (11). The threading machine is characterized in that an intermediate shaft (6) and a power head (9) are arranged on the threading machine, the power head (9) is connected with the upright column (2) by using the power head mounting frame (7), and the intermediate shaft (6) is connected with the motor (4) and the power head (9) via the V belts (5). Two belt pulleys arranged on the same axle are mounted on the intermediate shaft (6) and a spindle (13), and the rotation directions of the two belt pulleys are opposite to each other. When the threading machine is in work, power generated by the motor is transmitted to the V belt pulley on the intermediate shaft via the V belt, movement is then transmitted to the power head portion via the other V belt, an operator controls a sliding compact via a shifting fork, then controls the power head to drive the drill chuck to rotate forwards or backwards and consequentially completes threading or retracting action.