According to one embodiment, a pattern forming method includes forming a graphoepitaxy on a substrate, a process of forming a first self-assembly material layer that contains a first segment and a second segment in a depressed portion of the graphoepitaxy, a process of forming a first self-assembly pattern that has a first region containing the first segment, and a second region containing the second segment by performing a phase separation of the first self-assembly material layer, a process of forming a second self-assembly material layer containing a third segment and a fourth segment on a projected portion of the graphoepitaxy, and the first self-assembly pattern, a process of forming a second self-assembly pattern that has a third region containing the third segment, and a fourth region containing the fourth segment by performing a phase separation of the second self-assembly material layer.