An attitude-measurement system (TISS-5-40) has been developed to achieve a wearable sensor for individuals. This equipment is one of the inertial sensor systems having three fiberoptic gyroscopes and three accelerometers. Heading stability of 1 deg./hr. (1σ) and attitude accuracy of ±0.5 deg. have been demonstrated. At present, some of the attitude-measurement Systems have been applied in the field of mixed-reality technology, and the users confirm and report its effectiveness (Hara, Anabuki, Satoh, Yamamoto, & Tamura, 2000).