A molding apparatus includes a mold having a long cavity; a pinching member that holds a long metal plate having a pair of longitudinal ends, a pair of lateral ends and a pair of surfaces forming a plate shape by pinching the long metal member, the long metal plate being inserted into the cavity such that the longitudinal direction of the long metal plate is directed to a longitudinal direction of the cavity and the long metal plate is positioned at a position offset from a center of the cross-section of the circumferential surface; and an inlet for pouring a resin material into a space defined between the mold and the pinching member, wherein a shape of the space is such that the amounts of the resin material to be poured around the each side of the pair of surfaces of the long metal plate are equivalent.