According to one embodiment, a semiconductor device manufacturing method is disclosed. The method can include polishing a film on a semiconductor substrate by pressing the film against a polishing pad. Polishing the film comprises performing first polishing in which an entrance temperature of the polishing pad is adjusted to 40° C. (inclusive) to 50° C. (inclusive), and an exit temperature of the polishing pad is adjusted to be higher by 5° C. or more than the entrance temperature. Polishing the film comprises performing second polishing in which the entrance temperature is adjusted to 30° C. or less, and the exit temperature is adjusted to be higher by 5° C. or more than the entrance temperature.