A concentration measurement apparatus 1A includes a probe 20 being attached to a head and having a light source 21 for outputting measurement light and a photodetection unit 22 for generating a detection signal according to an intensity of incident light, a calculation unit 12 for performing a calculation of a hemoglobin concentration-related numerical value in the head which varies due to repetition of chest compression on the basis of the detection signal according to the intensity of the measurement light propagated through the inside of the head, and an instruction unit 13 for instructing the calculation unit 12 to start the calculation. The photodetection unit 22 continuously generates the detection signal before the calculation start in the calculation unit 12. The instruction unit 13 determines the calculation start on the basis of the detection signal. Thus, the concentration measurement apparatus and the concentration measurement method capable of automatically determining appropriate timing of the measurement start are realized.
