A method for manufacturing an interposer to connect boards or elements with different pin or pad spacings comprises following steps. A mold with first and second plates is provided. The first plate defines a plurality of first units with a plurality of first holes, the second plate defines a plurality of second units with a plurality of second holes. Space between central lines of adjacent first holes is different from that of adjacent second holes. Conducting wires pass through the first holes and the second holes, and molding compound is injected into the mold to keep the conducting wires in place. A molded plate defining a plurality of plate units is thereby formed, and molded pieces constituting interposers are obtained by cutting the molded plate.