PROBLEM TO BE SOLVED: To highly accurately acquire information about a concentration in photoacoustic measurement in a simplified manner.SOLUTION: There is provided a photoacoustic apparatus, comprising: a light source for emitting a plurality of light beams each having a different wavelength from one another； transducers for transforming, into electrical signals, acoustic waves generated from a subject irradiated with the plurality of light beams of different wavelengths； and signal processing means for acquiring information about distribution of concentration of a substance within the subject, using the electrical signals. The signal processing means acquires a plurality of sound pressure distribution information sets corresponding respectively to the plurality of light beams of different wavelengths, and acquires information about distribution of concentration of a substance within the subject, using the plurality of sound pressure distribution information sets, information about the concentration of a substance at a location within the subject determined based on a user instruction, and information about the light absorption of the substance for each of the light beams of different wavelengths.SELECTED DRAWING: Figure 3【課題】光音響測定において、簡易かつ高精度に濃度に関する情報を取得する。【解決手段】互いに異なる複数の波長の光を照射する光源と、複数の波長の光のそれぞれが照射された被検体から発生する音響波を電気信号に変換する変換素子と、電気信号を用いて被検体内の物質の濃度の分布情報を取得する信号処理手段を有し、信号処理手段は、複数の波長の光のそれぞれに対応する複数の音圧分布情報を取得し、複数の音圧分布情報、ユーザーからの指示に基づいて決定された被検体内のある位置における物質の濃度情報、及び複数の波長の光のそれぞれに対する物質による吸収に関する情報を用いて、被検体内の物質の濃度の分布情報を取得する光音響装置を用いる。【選択図】図３
