Abstract: A basic physical condition of a person is estimated. A biological state estimation device calculates a plurality of indexes indicating variations of states of bioregulation function elements, including an index ascribable to fluctuation highly correlated with a brain function, an autonomic nervous function, bodily and mental fatigue, or sensation, which are obtained from a bioregulation function element judging device, every predetermined judgment times set for the respective bioregulation function elements in advance to find time-series variations of the indexes. A basic physical condition estimating device analyzes the time-series variations in order of priorities. Consequently, it is possible to find a physical condition from fluctuation performance serving as a basis of a regulation system of a person in a basic physical condition estimation time which is set longer than the judgment times of the respective bioregulation function elements.