A controller to control an electronic musical instrument includes: first to third input units for a user to input play data and a frame having the first to third input units arranged therein. The frame has a wall surrounding an internal space, the wall has a three dimensional surface, the first to third input units configure one set, and the first to third input units configuring one such set are arranged adjacent in a circumferential direction of the three dimensional surface and the plurality of sets are arranged adjacent in a longitudinal direction of the three dimensional surface.