Screwing shaft device with torque-variable mechanism

The invention discloses a screwing shaft device with a torque-variable mechanism. The screwing shaft device comprises a support, a first screwing shaft, a second screwing shaft and the torque-variable mechanism, wherein a base plate is arranged above the support, a first mounting position and a second mounting position are arranged on the base plate, and the position between the first mounting position and the second mounting position is in a hollow shape; the first screwing shaft is fixedly mounted in the first mounting position through a mounting plate, and a first through hole allowing the working end of the first screwing shaft to penetrate through is formed in the middle of the mounting plate; and the torque-variable mechanism comprises two sliding rails, a sliding block and an adjusting screw rod, the end socket of the adjusting screw rod is fixedly connected with the sliding block through a pull block, and the adjusting screw rod is used for adjusting the distance between the second screwing shaft and