A compact 10 is obtained by compression-molding coated soft magnetic particles covered with insulating coatings, and is a modified frustum body having, as a main body, a frustum portion 113 sandwiched between plate-shaped portions 111 and 112 arranged in opposing relation. A vertical cross-section of the compact 10 is made up of a trapezoidal surface 113s, a long-side rectangular surface 111s joining to a long side of the trapezoidal surface 113s, and a short-side rectangular surface 112s joining to a short side of the trapezoidal surface 113s.