To provide a manufacturing method of a premold semiconductor device by which sealing resin does not adhere to upper faces of leads, resin removing work is not necessary, and wire is bonded with sufficient workability and reliability.

In the manufacturing method of the premold semiconductor device 24, a plurality of leads 11 installed around a semiconductor chip loading part 10 are resin-sealed by leaving an upper face of a semiconductor chip loading part 10, and a hollow part 22 is formed at an upper part where upper faces of the leads 11 are not resin-sealed and an upper part of the semiconductor chip loading part 10. A resist film 13 that can be removed by solvent is formed on the upper faces of a plurality of leads 11 before a plurality of leads 11 arranged around the semiconductor chip loading part 10 is resin-sealed. The resist film 13 is removed after resin sealing.