PROBLEM TO BE SOLVED: To stably measure the movement of a pupil even when a human has his eyes closed. A pupil measuring instrument 3 is a contact-type instrument provided with an antenna coil 30 and a measuring circuit 40, and is mounted between the back of a user's eyelid 101 and a cornea 102. The power supply unit 50 provided in the control circuit 41 of the measurement circuit 40 operates the measurement circuit 40 by using the electric power generated by electromagnetic induction. The element pair selection drive unit 52 sequentially selects one of the pair of the plurality of light emitting elements 42 and the light receiving element 43. The time difference calculation unit 53 outputs the emission signal to the light emitting element 42 to emit infrared light, inputs the reflected signal along with the input of the reflected light by the light receiving element 43, and calculates the time difference Δt of these signals. The boundary determination unit 54 determines the pupil 103, the iris 104, and the like at opposite positions based on the time difference Δt, and obtains the boundary coordinates between the pupil 103 and the iris 104. The measurement data generation unit 55 generates measurement data regarding the movement of the pupil 103 from the boundary coordinates. [Selection diagram] Fig. 6【課題】人間が目を閉じているときであっても、安定的に瞳孔の動きを測定する。【解決手段】瞳孔測定器具３は、アンテナコイル３０及び測定回路４０を備えたコンタクト型の器具であり、ユーザの瞼１０１の裏と角膜１０２との間に装着される。測定回路４０の制御回路４１に備えた電源部５０は、電磁誘導により発生した電力を用いて測定回路４０を動作させる。素子対選択駆動部５２は、複数の発光素子４２及び受光素子４３の対から１つを順番に選択する。時間差算出部５３は、発射信号を発光素子４２へ出力して赤外光を発射させ、受光素子４３による反射光の入力に伴い反射信号を入力し、これらの信号の時間差Δｔを算出する。境界判定部５４は、時間差Δｔに基づいて、対向する位置の瞳孔１０３、虹彩１０４等を判断し、瞳孔１０３と虹彩１０４との間の境界座標を求める。測定データ生成部５５は、境界座標から瞳孔１０３の動きに関する測定データを生成する。【選択図】図６
