PROBLEM TO BE SOLVED: To easily infer an index associated with energy of a living body.SOLUTION: An energy index inference part 24 uses an inference model to estimate indexes other than one unknown index amount three indexes, i.e. an index associated with energy that a living body takes in a predetermined period (an index associated with a feature quantity of temporal variation in living body reaction signal value originating from a meal eaten after a meal is finished) an index associated with energy that the living body consumes in the predetermined period, and an index associated with the quantity of variation in energy accumulated in the living body in the predetermined period. Further, a model parameter decision part 26 infers the unknown index based upon a relational expression that the three indexes satisfy and inference results of the indexes other than the unknown index, and also generates one of model parameters of the inference model other than the two previously acquired parameters based upon the two previously acquired model parameters and inferred values of the three indexes.SELECTED DRAWING: Figure 3【課題】生体のエネルギーに係る指標を簡単に推定する。【解決手段】エネルギー指標推定部２４は、所定期間において生体が摂取したエネルギーに係る指標（食事終了後の食事に由来する生体反応信号値の経時変化の特徴量に関連する指標）と、所定期間において生体が消費したエネルギーに係る指標と、所定期間において生体に蓄積されたエネルギーの変化量に係る指標と、の３つの指標のうち、１つの未知の指標以外の指標を推定モデルを用いて推定する。また、モデルパラメータ決定部２６は、３つの指標が満たす関係式と、未知の指標以外の指標の推定結果とに基づいて、未知の指標を推定するとともに、推定モデルのモデルパラメータのうち、予め取得した２つ以外の１つを予め取得した２つのモデルパラメータと３つの指標の推定値に基づいて生成する。【選択図】図３
