This invention provides a particle beam irradiating device, which aims to obviously reduce total amount of multiple excess dose which is caused by delay in blocking beams in a spot scanning.The particle beam irradiating device (50) includes: a dose monitor (5) for measuring an excess dose (14) which is irradiated from the time when the measured dose reaches a divided target dose to the time when irradiation of the beams (10) is blocked a controller (4) of the particle beam irradiating (50) controlling a beam generating-transporting device (1) and a scanning device (2) such that the following operation is repeated by a predetermined number of times for all of the irradiation locations (12): in irradiation on an irradiated location (12) at second time or after second time, when the dose monitor (5) detects the dose reaching a previous excess dose (14) on the irradiated location (12) from a compensation dose, which is the value obtained by the divided target dose, the beam generating-transporting device (1) blocks the irradiation of the beams (10), and then a scanning device (2) performs a deflection control corresponding to the next irradiated location (12), and then the beam generating-transporting device (1) performs the irradiation of the beams (10) again.本發明提供一種粒子線照射裝置,其目的為在點掃描法中,使起因於射束遮斷之延遲的複數次之過度線量之總量明顯地減少。粒子線照射裝置(50),係具備有:線量監視器(5),用以量測從量測之線量達到分割目標線量之值起至粒子線(10)之照射被遮斷為止之間所照射的過度線量(14);而粒子線照射裝置(50)之控制部(4)將粒子線產生傳輸裝置(1)及掃描裝置(2)控制為,對全部的照射位置(12)重複下述操作達預先指定之次數:在對於照射位置(12)之第二次以後之照射時,當藉由線量監視器(5)所量測之量測線量,到達從分割目標線量之值減去在該照射位置(12)之前一次過度線量(14)之值的補償線量值時,令粒子線產生傳輸裝置(1)遮斷粒子線(10)之照射,且使掃描裝置(2)進行與下一個照射位置(12)相對應之偏向控制之後,令粒子線產生傳輸裝置(1)再次開始粒子線(10)的照射。1‧‧‧粒子線產生傳輸裝置2‧‧‧掃描裝置3‧‧‧記憶部4‧‧‧控制部5‧‧‧線量監視器10‧‧‧粒子線11‧‧‧照射對象12‧‧‧照射位置21‧‧‧X方向掃描裝置22‧‧‧Y方向掃描裝置50‧‧‧粒子線照射裝置
