To provide a semiconductor device having excellent characteristics.

A semiconductor device manufacturing method comprises the steps of: coating on a semiconductor substrate 10, a doping substance containing a dopant of a first conductivity type or a second conductivity type different from the first conductivity type; and forming diffusion layers 12, 13 by causing the dopant to diffuse from the coated doping substance to the semiconductor substrate. The method further comprises at least one of the steps of: heating the semiconductor substrate at at least one moment of time before coating, during coating and after coating the doping substance; heating the doping substance at at least one moment of time during coating and after coating the doping substance; and irradiating light on the doping substance at at least one moment of time during coating and after coating the doping substance.