In the manufacture of a load beam for reading and writing a hard disk in a hard disk drive which load beam has a body having a slope extending from a front end thereof and bent along a bend line in a direction opposite to the hard disk, a tab protruding from the slope and to be guided on a guide of the hard disk drive, and a box-bent portion extending along each side edge of the body and slope and passing through an end of the bend line. A first stage is preparing a load beam material that is flat and has a deformation control zone on a section to be processed into the box-bent portion of the load beam material corresponding to the section to be processed into the bend line so as to prevent the box-bent portion from deforming and protruding when the box-bent portion is formed.