The purpose of this research is to establish a scale for comfort with regard to whole-body vibration by the category judgment method. Experiments were conducted with random signals as stimuli. These stimuli consisted of three types of signal, namely stimulus F, with flat PSD (Power Spectrum Density) ranging from 1 to 100 Hz, stimulus H with PSD, which became 20 dB higher at 100 Hz than at 1 Hz,...