At a timing at which a music playing operation is made by way of a music playing member, it is determined whether the position coordinates of the music playing member belong to any of a plurality of regions arranged on a virtual plane based on layout information store in memory, and in a case of having determined as belonging to the region, it is determined whether the pitch angle of the music playing member detected by way of a pitch angle sensor belongs to the pitch angle range corresponding to the region, and in the case of having determined as belonging to the pitch angle range corresponding to the region, the generation of a sound of a musical note corresponding to the region is instructed.