The invention relates to a straightening machine. The current straightening machine has a vertical structure and has a problem that the bent site of a steel pipe is hardly erected perpendicular to a horizontal plane and is often crushed down at the time not yet being erected in the case of being loaded by a master cylinder, resulting in troublesome operation, low operating efficiency and poor straightening effect. The straightening machine comprises a principal machine and auxiliary equipment. The principal machine has a horizontal structure with a U-shaped frame, a joist device containing a pivot movable press head is connected with one end of the frame, and an operating cylinder device containing a main press head is connected with the other end of the frame; and the auxiliary equipmentcomprises carrying roller brackets, carrying rollers, lifting supports, rotary support rollers and pedestals, which are symmetrically arranged on the two sides of the principal machine. The straightening machine can lift the bent site of the steel pipe (bar) to a straightening center via the auxiliary equipment, and then the master cylinder applies a horizontal load for straightening, so that theinvention has the advantages of good straightening effect and high operating efficiency.