An object information acquiring apparatus comprises a first light source configured to generate first irradiation light a second light source configured to generate second irradiation light a first illumination optical system configured to guide the first irradiation light to the object a second illumination optical system configured to guide the second irradiation light to the object a light sensor unit configured to acquire an intensity signal of the reflected second irradiation light on the object and a control device configured to determine irradiation propriety of the first irradiation light on the basis of the intensity signal of the reflected light. The second illumination optical system shares at least a part of an optical member with the first illumination optical system.
