PROBLEM TO BE SOLVED: To provide a particle beam irradiation device capable of setting the cumulative particle number of particle beams to be emitted to an arbitrary value.SOLUTION: A particle beam irradiation device comprises: an accelerator 2 for emitting a pulsed particle beam; shielding means 5 having a function of shielding the pulsed particle beam emitted from the accelerator 2 so as not to irradiate an irradiation object 4; a database 7 in which time dependency of the particle number in one pulse of a particle beam is stored corresponding to a drive condition of the accelerator 2; calculation means 8 for calculating timing of a shielding operation of the shielding means 5 on the basis of a target cumulative particle number to be emitted to the irradiation target 4 and the time dependency of the particle number in one pulse of a particle beam which is stored in the database 7; and shielding control means 6 for controlling the shielding means 5 on the basis of the timing of the shielding operation of the shielding means 5 which is calculated by the calculation means 8.SELECTED DRAWING: Figure 1【課題】照射する粒子線の累積粒子数を任意の値に設定することができる粒子線照射装置を得ることを目的とする。【解決手段】パルス状の粒子ビームを出射する加速器2と、この加速器2から出射されるパルス状の粒子ビームが照射対象物4に照射されるのを遮蔽する機能を備えた遮蔽手段5と、加速器2の駆動条件に対応して粒子ビームの1パルスにおける粒子数の時間依存性が記憶されたデータベース7と、照射対象物4に照射する目標累積粒子数とデータベース7に記憶された粒子ビームの1パルスにおける粒子数の時間依存性とに基づいて遮蔽手段5の遮蔽動作のタイミングを算出する演算手段8と、演算手段8で演算された遮蔽手段5の遮蔽動作のタイミングに基づいて遮蔽手段5を制御する遮蔽制御手段6とを備えたものである。【選択図】図1