PROBLEM TO BE SOLVED: To estimate with high accuracy a physiological day determined by either one of two physiological cycles whose cycles are different from each other. SOLUTION: The cycle determination unit 34 determines whether the current menstrual cycle is a first menstrual cycle or a second menstrual cycle, and the next ovulation day or menstrual day based on the judged menstrual cycle. And the estimation part 35 which estimates. [Selection diagram] Figure 1【課題】その周期が互いに異なる２つの生理周期のいずれか一方で定まる生理日を高い精度で推定する。【解決手段】現在の生理周期が第１の生理周期と第２の生理周期とのいずれであるかを判断する周期判断部３４と、判断された生理周期に基づいて次回の排卵日や生理日を推定する推定部３５とを有する。【選択図】図１
