The invention provides a tool rest device for cutting films of a steel belt. The tool rest device comprises hobs, a round handle, a screw rod, a locating block, a supporting plate, two clamping plates, a sliding block and tool rests. The hobs are arranged at the tail ends of the tool rests, the locating block is fixed to the supporting plate, and the supporting plate achieves the function of supporting the tool rest device. The screw rod penetrates through a threaded hole of the locating block, the round handle is fixed to the upper end of the screw rod, the lower end of the screw rod is connected with the sliding block through the two clamping plates, and the screw rod can rotate in a circle formed by the two clamping plates and cannot be separated from the circle. According to the tool rest device, the round handle is rotated, the screw rod can be driven to precisely adjust the vertical height of the sliding bock, and then the size of the cut films of the steel belt and the pressure between the hobs and the steel belt can be precisely controlled.