A polygonal mirror fixing device comprising a rotary body, to which a polygonal mirror is adapted to be mounted, has a mounting circumferential surface in a center opening of the polygonal mirror and a mounting bottom surface which projects from the mounting circumferential surface in the radially outward direction. In the case where an extent of flexion of the leg link 3 is not more than a predetermined extent, the coil spring 14 applies, to a third joint 8, a first biasing force for preventing the extent of flexion of the leg link 3 from decreasing due to gravity acting on a body weight support device A. The indirect receiving unit is preferably formed of a communication device provided with a wireless cellular telephone function using a wideband code division multiple access system in which signals having a large transmission capacity can be transmitted and received, or a communication device provided with a wireless LAN communication function. The layer-by-layer growth of metal deposited onto the oxide surface is promoted because the adhesion strength of the metal-oxide interface is increased. The second read mode is for performing parallel data transfer of a greater bit number than that of the first read mode when sending data from the memory cell array to the read circuit while performing data transfer of a smaller bit number than the bit number when sending data from the read circuit up to the external terminal. The generation and feedback system further includes a light generator and an electrical circuit connected to the sound generator for intermittent generation of sound and light in proportion to the rotation of the training wheel.