A semiconductor device manufacturing method includes: a pretreatment step of performing a hydrophobic treatment on a first exposed region of an exposed surface, an n-type semiconductor layer being exposed from the first exposed region, and a pn junction being exposed from the exposed surface; an impurity supplying step of supplying an n-type impurity to the first exposed region; a channel stopper forming step of irradiating the first exposed region with a laser beam to introduce the n-type impurity into the n-type semiconductor layer, thus forming a channel stopper; and a glass layer forming step of forming a glass layer using a glass composition so as to cover the exposed surface.