The performances of a semiconductor device are improved. A method for manufacturing a semiconductor device includes the steps of: providing a semiconductor substrate having a gettering layer formed by ion implanting a cluster, and an epitaxial layer; subjecting the semiconductor substrate to a heat treatment at 800° C. or more, and thereby forming a hydrogen adsorption site; forming an element isolation film at the semiconductor substrate, to be performed thereafter; implanting an impurity for forming a first semiconductor region in the semiconductor substrate; implanting an impurity for forming a second semiconductor region; and performing a heat treatment for a photodiode, to be performed thereafter.