A die apparatus for molding an arcuate magnet having polar-anisotropic orientation in a magnetic field, which comprises a die made of non-magnetic cemented carbide, which is arranged in a parallel magnetic field generated by a pair of opposing magnetic field coils; an arcuate-cross-sectional cavity having an inner arcuate wall, an outer arcuate wall and two side walls, which is disposed in the die; a central ferromagnetic body arranged on the side of the outer arcuate wall of the cavity; and a pair of side ferromagnetic bodies symmetrically arranged on both side wall sides of the cavity; the cavity being arranged such that its radial direction at a circumferential center thereof is identical with the direction of the parallel magnetic field; the width of the central ferromagnetic body being smaller than the width of the cavity in a direction perpendicular to the parallel magnetic field; and a pair of the side ferromagnetic bodies being arranged such that the cavity is positioned in a region sandwiched by a pair of the side ferromagnetic bodies.