Component concentration measuring device

A component concentration measuring device comprising:

• a pair of holding members including a first holding member and a second holding member that are configured to clamp a measurement site of a measurement subject;
• a light emitting device configured to emit a light beam having a wavelength absorbed by a measurement target substance from the first holding member toward the measurement site;
• a detector housed in the second holding member and configured to detect a photoacoustic signal generated by the measurement site when irradiated with the light beam;
• a matching member configured to be arranged between the second holding member and the measurement site, and is configured to perform acoustic matching between the detector and the measurement site by undergoing elastic deformation with a constant elastic modulus while in contact with the measurement site;
• and
• a resonator configured to cause the photoacoustic signal to resonate, the resonator being constituted by a first reflector that is arranged between the first holding member and the measurement site and has a first reflection surface configured to reflect the photoacoustic signal while allowing the light beam to pass therethrough, and a second reflector that is arranged between the second holding member and the measurement site and has a second reflection surface configured to reflect the photoacoustic signal, wherein the matching member fills a gap between the second reflector and the measurement site when the measurement site is clamped between the pair of holding members, and wherein a distance between the first reflection surface and the second reflection surface is a distance at which the photoacoustic signal resonates;
• wherein:
• the first reflection surface and the second reflection surface are parallel with each other,
• the second reflection surface faces the measurement site, and
• the second reflector includes a second contact surface that faces the second holding member and is in contact with a detection surface of the detector housed in the second holding member, wherein the detection surface faces the measurement site, and a void is disposed between the second reflection surface and the second contact surface.