There are provided a first mold 2 and a second mold 1 that can be brought into and released from contact with the first mold 2. A substrate 70 provided in both the molds 1, 2 and mounted with electronic components is subjected to resin sealing and molding by filling with resin of cavities formed by both the molds 1, 2. The second mold 1 is placed on a base plate 9 so as to be capable of horizontally reciprocating, and has a cavity block 7 that can be brought into and released from contact with the first mold 2 and a mold clamping mechanism 16 that supports the cavity block 7 and that brings and releases the cavity block 7 into and from contact with the first mold 2 so as to perform mold clamping. On the base plate 9 is provided a horizontal actuation mechanism 11 for moving the second mold 1 to a facing position where the second mold 1 faces the first mold 2 and to a non-facing position where the second mold 1 has been moved sideways from the facing position.