A particle beam adjustment device includes: a position monitor that detects a positional deviation of a particle beam transported from a beam transport section； an interlock device to interrupt irradiation of the particle beam when a positional deviation of the particle beam is detected by the position monitor； a pair of screen monitors that measure position and angle of an axis of the particle beam； a correction electromagnet that controls the axis of the particle beam by adjusting a magnetic field on a basis of a signal indicating the particle beam position and angle measured by the screen monitors； and a beam scanning electromagnet that irradiates an irradiation target with the particle beam. One of the screen monitors is installed outside a treatment room, and the other screen monitor and the position monitor are installed inside the treatment room.
