The purpose of the present invention is to provide a particle therapy device by scanning irradiation, the device being capable of adequately calibrating dose. That is, there is provided a particle therapy device comprising: an irradiation nozzle for moving a pencil beam in a lateral direction which is in a direction vertical to a direction of movement a dose monitor for measuring the dose of a particle beam exiting the irradiation nozzle a therapy planning portion for setting an irradiation dose setting value for irradiating to an irradiation target and a therapy control portion containing an irradiation dose controller for controlling the irradiation dose for irradiating to an irradiation target based on a measured value by the dose monitor and the irradiation dose setting value set by the therapy planning portion, wherein the therapy planning portion stores PDD, which is absorbed dose distribution data in the depth direction prepared in advance, with an absorbed dose at a reference depth rather than at a Bragg peak position as a reference, the reference depth being a predetermined position on the side where the pencil beam enters, and calculates the irradiation dose setting value with the absorbed dose at the reference depth as the reference.La présente invention concerne un dispositif de thérapie par particules réalisant une irradiation à balayage, le dispositif étant capable détalonner la dose de façon adéquate. Plus précisément, linvention concerne un dispositif de thérapie par particules comportant : une buse dirradiation servant à déplacer un faisceau filiforme dans une direction latérale qui se situe dans une direction verticale par rapport à une direction de mouvement un élément de surveillance de la dose servant à mesurer la dose dun faisceau de particules sortant de la buse dirradiation une partie de planification de thérapie servant à fixer une valeur de réglage de dose dirradiation à irradier vers une cible dirradiation et une partie de commande de t
