The present invention has the objective of providing a particle beam irradiation apparatus which, with a simple structure, is capable of checking the operation of a scanning mechanism and which has a relatively high reliability. The particle beam irradiation apparatus is provided with a particle beam shield (6) for shielding a portion of a scanned particle beam (4), an immediate signal detector (11) for detecting an immediate signal that is generated when the particle beam (4) which is scanned to the particle beam shield (6) hits the shield, and a signal comparison device (12) which predicts a pattern of generation of the immediate signal that is generated by a pre-determined scanning pattern and obtains the pattern to store thereof as a signal time pattern for comparison wherein the signal comparison device (12) compares the detected signal time pattern, which is the time pattern of the signal detected at the immediate signal detector (11) when the particle beam was scanned according to the pre-determined scanning pattern and the particle beam was irradiated upon a target, and the stored signal time pattern for comparison, so as to detect an anomaly of the particle beam scanning or the particle beam shield (6).La présente invention concerne un appareil produisant un faisceau de particules qui, malgré une structure simple, est capable de vérifier le fonctionnement dun mécanisme de balayage et qui présente une fiabilité relativement élevée. Lappareil produisant un faisceau de particules comprend un blindage pour faisceau de particules (6) servant à faire écran à une partie du faisceau de particule balayé (4), un détecteur de signal immédiat (11) servant à détecter un signal immédiat qui est généré quand le faisceau de particules (4) qui est balayé sur le blindage pour faisceau de particules (6) frappe le blindage, et un dispositif de comparaison de signaux (12) qui prédit un profil de génération du signal immédiat qui est généré par un profil de balayage prédéterminé
