Particle beam therapy system and adjustment method for particle beam therapy system

A particle beam therapy system, comprising:

• a scanning electromagnet provided with two scanning electromagnets that perform control to scan a supplied charged particle beam in respective different directions so that the charged particle beam is formed in a three-dimensional irradiation shape based on a treatment plan;
• and
• a deflection electromagnet that switches orbits for a charged particle beam in such a way that the charged particle beam with which scanning is performed by the scanning electromagnet heads for an isocenter through a single beam orbit selected from a plurality of beam orbits for multi-port irradiation established between the isocenter and the scanning electromagnet,
• wherein the deflection electromagnet includes a first deflection electromagnet that is provided at the downstream side of the scanning electromagnet and deflects a charged particle beam with which scanning has been performed by the scanning electromagnet, in accordance with the selected orbit;
• and a second deflection electromagnet that is provided at the downstream side of the first deflection electromagnet and deflects to the isocenter a charged particle beam that has been deflected by the first deflection electromagnet.