A method of producing a resin-sealed package is provided with: providing an electronic component which has a plurality of terminals on one face, a first support member and a second support member; temporarily fixing said electronic component to a surface of said first support member by a first adhesive agent layer, to face said terminals with said first support member; fixing said second support member having a second adhesive agent layer to said electronic component while interposing said electronic component between said first support member and said second support member to face said second adhesive agent layer with a back face side of said electronic component; resin sealing said electronic component between said first support member and said second support member; peeling said first support member and said first adhesive agent layer from said electronic component and a sealing resin; and stacking an insulating resin layer and a wiring layer which is electrically connected to said terminals of said electronic component, on said electronic component and said sealing resin.