The invention provides a probe for measuring the local dynamics of blood which improves a test precision and is easily installed to a test subject. In a probe device including a light irradiating portion, and a light detecting portion, the probe device is provided with a sheet-like probe holding body (200), light emitting probes (300) and detection probes (400) which are attached to the probe holding body (200) at a predetermined interval. The device further comprises a board holding portion (241) attached to the probe holding body (200), an electronic board (1000) attached to the board holding portion (241), a sheet holding portion (500) holding the probe holding body (200) at the head of the test subject, and a fixing band (600). The electronic board (1000) is provided with probe control boards (243) controlling respective motions of the light emitting probes (300) and the detection probes (400), and a main control board (242) controlling the probe control boards (243) and communicating with the other devices.
