Body exercisers, usable in a plurality of modifications, encouraging exercising on sports training devices through users’ emotional stimulation and intended for group exercising, games and team contests. The further transition metal used is preferably Fe, Ni, Cu and Co. The position fixing ring is disposed center of the fixing ring and the position fixing member of the position fixing ring, wherein the position fixing member is rotated using a special tool to disassemble the barrel disposed between the position fixing ring and the sight device, thereby achieving the objective of rapid disassembly, replacement and assembly of the barrel. A controller moves a display position of the image of the operator interface on the touch panel display in a direction in which an information processing apparatus tilts, according to changes in the apparatus posture detected by the tilt detector.