This photoacoustic wave detector is provided with: an internal light source (212) that comprises an LED element (212a) to be inserted into the interior of a subject (P) and that irradiates an object to be detected (Q) within the subject with light emitted from the LED element and an internal acoustoelectric conversion unit (22) that detects a photoacoustic wave generated at the object to be detected in the interior of the subject (150) and generates an internal detection signal that is based on the detection result of the photoacoustic wave (AW).