Abstract: A method for manufacturing a box-shaped door, which comprises the steps of cutting off the four corners of a rectangular metal blank in the square form to provide the four walls of a box body; vertically bending said cutoff four sides by a female die on whose inner wall there are provided in the stepped state an upper bending section and lower shaping section and a male die whose outer wall is shaped complementary to the inner wall of said female die; curvedly shaping the abutting edges of the corners of the four sides of the metal blank, said vertical bending and curved shaping being carried out at the same time; and welding said abutting edges to provide the box body of a box-shaped door.