A method of manufacturing a semiconductor device includes a step of forming a device region 5 that is separated by a device-separation insulating film 4 formed in a part of an SOI layer, a step of forming a gate insulating film 6a on a device region 5 so that the device region 5 can be exposed on both sides of the gate insulating film 6a, a step of forming a gate electrode 7a with polysilicon on the gate insulating film 6a, a step of adjusting the area of exposed silicon so that the area of exposed silicon can be a prescribed area by forming at least either a pseudo region 5b or a pseudo electrode 7b to control the growth rate in growing an epitaxial layer 9, and a step of conducting low-temperature epitaxial growth of silicon.