There is provided a photo acoustic probe which prevents foreign substances from entering and of which a portion of a light emitting unit to be easily damaged can be replaced. An acoustic wave detector 24 detects acoustic waves. First and second light guide members 21 and 23, which form the light emitting unit, are arranged in series in a traveling direction of light. A frame body 11 holds the first light guide members 21, the second light guide members 23, and the acoustic wave detector 24. The first light guide members 21, is positioned close to a subject, is undetachably fixed to the frame body 11. Meanwhile, the second light guide members 23, which is positioned close to a light source, is detachably fixed to the frame body 11.