1. A particle beam emitting apparatus comprising: an accelerator for extracting a charged particle beam; a beam delivery apparatus having a charged particle beam scanning unit and irradiating the charged particle beam extracted from the accelerator; and a controller that stops the irradiation of the charged particle beam from the beam delivery apparatus, that, in a state where the irradiation of the charged particle beam is stopped, controls the charged particle beam scanning unit to change the irradiation position of the charged particle beam and to start the irradiation of the charged particle beam from the beam delivery apparatus after said change, and that is configured to determine the occurrence of an abnormality based on an elapsed time from the irradiation start of the charged particle beam with respect to one said irradiation position, said controller controlling said charged particle beam scanning unit such that for each of a plurality of irradiation positions set for each of a plurality of layer regions in an affected part, the beam irradiation at one position is performed a plurality of times so as to divide the irradiation at each position into plural irradiations, said elapsed time being an elapsed time from the start of irradiation in each of the divided irradiations when the beam irradiation at one position is performed a plurality of times.