A method for manufacturing a semiconductor device includes epitaxially growing a carrier-transport layer of a first conductivity type on a substrate of silicon carbide; irradiating the carrier-transport layer with a first light having a wavelength equal to or less than an absorption-edge wavelength of silicon carbide at a temperature of less than 400 degrees Celsius so as to expand a stacking fault originating from a basal plane dislocation which are propagated from the substrate to the carrier-transport layer; heating the carrier-transport layer in which the stacking fault has expanded so as to shrink the stacking fault, at a shrinking temperature of 400 degrees Celsius or more and 1000 degrees Celsius or less; and forming a carrier-injection region of a second conductivity type on the carrier-transport layer, the carrier-injection region injects carriers into the carrier-transport layer.