A probe (1) is used in an optical coherence tomography device which irradiates measurement light to a subject and collects scattered light that has returned from the subject after being reflected. The probe (1) is provided with a scanning means (70) composed of galvanometer mirrors (72, 73) that change an irradiation direction of the measurement light. The scanning means (70) is provided with actuators (72b, 73b) which switch reflecting mirrors (72a, 73a) that reflect the measurement light between a state where the measurement light is reflected by the subject and returns as the scattered light, and a state where the measurement light is diffusely reflected within the probe (1).