An object of the present invention is to provide a musical performance device by which the arrangement of a virtual musical instrument set is suitably changed based on the position of the instrument player, and whereby the instrument player need not play in an uncomfortable position. In the present invention, set layout information includes standard set layout information that serves as reference for the arrangement of a plurality of virtual pads, and a CPU judges whether an operation to form a square has been performed with a pair of drumstick sections. When judged that this operation has been performed, the CPU uniformly adjusts the arrangement of the virtual pads based on preset position coordinates on a captured image plane corresponding to the standard set layout information and the position coordinates of the drumstick sections on the captured image plane at the time of the operation to form a square.