According to one embodiment, a pattern formation method includes forming a resist pattern on an underlying film, slimming the resist pattern, forming a pinning portion having affinity for a first polymer by depositing, on a surface of the slimmed resist pattern, an etching product produced by etching the underlying film, forming a neutral, film having affinity for the first polymer and a second polymer on the underlying film after the etching, forming a block copolymer film containing the first polymer and the second polymer on the pinning portion and the neutral film, forming a microphase separation pattern by applying a predetermined process to the block copolymer film to perform microphase separation.