The invention of the present application is a die for compressing and sizing a sintered body (1) at straight portions (11, 21). Upper taper portions (15, 25) are provided on a die upper portion (13) and a core rod upper portion (23), and the straight portions (11, 21) are provided at a die lower portion (14) and a core rod lower portion (24). The materials of the die upper portion (13) and the core rod upper portion (23) have Young's moduluses higher than those of the materials of the die lower portion (14) and the core rod lower portion (24). The die upper portion (13) and the core rod upper portion (23) are made of materials having Young's moduluses that are at least 50 GPa higher than that of the sintered body (1). Thus, the sintered body (1) can be densified with a smaller ironing margin (s). Further, since the sintered body (1) is ironed without being compressed, by the taper portions of the die upper portion (13) and core rod upper portion (23) that are made of materials having high Young's moduluses, the die can be prevented from breaking, and being abraded due to ironing.