To provide a screw type bend correcting machine for steel material at a low cost by compactly simplifying a large-scaled hydraulic machine.

A screw (male screw) 7 and a pressurizing shaft 11 are integrated and they are moved with a rotary female screw 5 for horizontally moving by small force. Many pin holes 13 are beforehand bored on a pedestal 9 on which a steel material is loaded. Two pins 8 of a supporting shaft are inserted into the pin holes 13 in accordance with the shape of the steel material. The pressurizing shaft 11 is put on a place where force is expected to be added to the steel material. Pressure is applied to the steel material with the pressurizing shaft 11 by revolving the female screw 5 with a driving motor 1.