According to one embodiment, a pattern formation method includes forming a structure body on a first surface of a patterning member, the structure body having protrusions and a recess. The protrusions are arranged at a first pitch along a first direction. The first direction is aligned with the first surface. The recess is between the protrusions. The method further includes forming a resin film of a block copolymer on the structure body. The block copolymer includes first portions and second portions. The first and second portions are arranged alternately at a second pitch along the first direction. The structure body includes first and second regions. The first portions are on the first regions. The second portions on the second regions. The method further includes removing the second portions and the second regions, introducing a metal to the first regions, and etching the patterning member using the first regions.