A plating layer of a Cu-M-based alloy (M represents Ni and/or Mn) is formed on an end surface of a connection terminal member at an exposed side, the Cu-M-based alloy being capable of generating an intermetallic compound with an Sn-based low-melting-point metal contained in a bonding material forming a bonding portion and having a lattice constant different from that of the intermetallic compound by 50% or more. In the reflow process, even if the bonding material is about to flow out by re-melting thereof, since the bonding material is brought into contact with the Cu-M-based plating layer, a high-melting-point alloy of the intermetallic compound is formed so as to block the interface between the connection terminal member and the resin layer.