Provided is a particle beam irradiation apparatus capable of highly reliable measurement of a dose of each beam and capable of highly sensitive measurement of a leakage dose caused by momentary beam emission. The particle beam irradiation apparatus according to the present invention includes: an emission control portion that controls emission and termination of a particle beam a control portion that sequentially changes an irradiation position of the particle beam relative to an affected area first and second dosimeters that measure dose rates of the particle beam directed to the affected area and an abnormality determination portion that accumulates the dose rates output from the first and second dosimeters for each of predetermined determination periods to calculate first and second sectional dose measurement values and that performs second abnormality determination of determining that there is an abnormality and outputs an interlock signal for terminating the emission of the particle beam in at least one of a case in which the first sectional dose measurement value exceeds a predetermined first reference range and a case in which the second sectional dose measurement value exceeds a predetermined second reference range.
