In a living body inspection apparatus to inspect RLS (Restless Legs Syndrome), a pulse interval is obtained from a pulse wave signal, thereby performing a frequency analysis of the obtained pulse interval using CDM. From a result of the frequency analysis, the low frequency components ranging from 0.04 to 0.15 Hz and the high frequency components ranging from 0.15 to 0.4 Hz are extracted. A value of low frequency components (LF)/high frequency components (HF) is obtained as an index to which an amendment based on age is applied. It is then determined whether LF/HF is equal to or greater than a predetermined determination value indicating RLS. For example, it is determined whether LF/HF is equal to or greater than 0.65, which suspects RLS. It is determined whether a signal is accurately calculated which indicates an activity of autonomic nerve. A state of RLS is determined using LF/HF.