The present invention facilitates positioning of contact surfaces of a resin case, core gap management, and assembling processing. A resin case 1 can house at least one magnetic core selected from a U-shaped magnetic core, a UU-shaped magnetic core, a UR-shaped magnetic core, and an I-shaped magnetic core. The resin case 1 is used for an inductance element in which a coil is arranged around the magnetic core so as to house the magnetic core. The resin case is an assembly of a plurality of divided members with the same shape. A recess and a projection A1, A2 mutually fitted complementary to each other are formed on end surfaces of the divided members contacted with each other.