HAT-SHAPED STEEL SHEET PILE MANUFACTURING METHOD AND MANUFACTURING EQUIPMENT

To provide a hat-shaped steel sheet pile manufacturing method and manufacturing equipment which can suppress retraction deformation of an arm equivalent part and suppress flange wave generation when elongating a flange equivalent part in a rolled material by groove rolling.SOLUTION: When a rolling reduction of an arm equivalent part 54 is represented by ra, a rolling reduction of a web equivalent part 52 is represented by rw, a rolling reduction of a flange equivalent part 53 is represented by rf, a length of the flange equivalent part 53 on a rolling inlet side is represented by Lf0, and an extension amount of the flange equivalent part 53 is represented by ΔLf when elongating a length of the flange equivalent part 53, rolling is performed so as to satisfy the following formulae (A) to (D) : (A) (1-ff)×ΔLf/Lf0