An irradiation apparatus for a host vehicle comprising: a shielded object detecting unit configured to detect an object to be shielded from light emitted from the irradiation apparatus; the object being called shielded object; an illumination upper limit estimating unit configured to estimate an upper limit of an illumination brightness value with which the shielded object is to be irradiated, wherein glare is allowable to the shielded object at the upper limit of the illumination brightness or less; an illumination lower limit estimating unit configured to estimate a lower limit of the illumination brightness value with which the shielded object is to be irradiated, wherein a driver of the host vehicle can visually recognize the shielded object at the lower limit of the illumination brightness or more; an illumination setting unit configured to set the illumination brightness value to be between the upper limit of the illumination brightness estimated by the illumination upper limit estimating unit and the lower limit of the illumination brightness estimated by the illumination lower limit estimating unit; an irradiating device (50, 52) configured to irradiate a periphery of the host vehicle with light in an irradiation pattern; and an illumination controlling unit configured to control the irradiating device based on a relative position of the shielded object relative to the host vehicle and the illumination brightness set by the illumination setting unit, such that light is emitted in a predetermined irradiation pattern in which a first part of the shielded object is illuminated at the illumination brightness value set by the illumination setting unit and a second part of the shielded object is illuminated at a higher illumination brightness than the illumination brightness value set by the illumination setting unit when seen from the host vehicle, the second part not including the first part, characterized in that the illumination upper limit estimating unit is configured to estimate the upper limit of the illumination brightness value based on the relative position of the shielded object detected by the shielded object detecting unit relative to the host vehicle, the illumination lower limit estimating unit is configured to estimate the lower limit of the illumination brightness value based on a brightness of a background of the shielded object. a shielded object detecting unit configured to detect an object to be shielded from light emitted from the irradiation apparatus; the object being called shielded object; an illumination upper limit estimating unit configured to estimate an upper limit of an illumination brightness value with which the shielded object is to be irradiated, wherein glare is allowable to the shielded object at the upper limit of the illumination brightness or less; an illumination lower limit estimating unit configured to estimate a lower limit of the illumination brightness value with which the shielded object is to be irradiated, wherein a driver of the host vehicle can visually recognize the shielded object at the lower limit of the illumination brightness or more; an illumination setting unit configured to set the illumination brightness value to be between the upper limit of the illumination brightness estimated by the illumination upper limit estimating unit and the lower limit of the illumination brightness estimated by the illumination lower limit estimating unit; an irradiating device (50, 52) configured to irradiate a periphery of the host vehicle with light in an irradiation pattern; and an illumination controlling unit configured to control the irradiating device based on a relative position of the shielded object relative to the host vehicle and the illumination brightness set by the illumination setting unit, such that light is emitted in a predetermined irradiation pattern in which a first part of the shielded object is illuminated at the illumination brightness value set by the illumination setting unit and a second part of the shielded object is illuminated at a higher illumination brightness than the illumination brightness value set by the illumination setting unit when seen from the host vehicle, the second part not including the first part, characterized in that the illumination upper limit estimating unit is configured to estimate the upper limit of the illumination brightness value based on the relative position of the shielded object detected by the shielded object detecting unit relative to the host vehicle, the illumination lower limit estimating unit is configured to estimate the lower limit of the illumination brightness value based on a brightness of a background of the shielded object.