A phototherapy device including: an irradiation probe for radiating irradiation light toward a living body; a probe fixing unit into which the irradiation probe is inserted and at the same time fixed on a living body; an observation module placed on the probe fixing unit and provided with an observation means for observing an irradiation site irradiated with irradiation light which is radiated to the living body; and a moving means capable of moving the observation module to a space where the irradiation probe is to be placed in the probe fixing unit during observation of the irradiation site.