A particle therapy system includes a building having a first floor and second floors and, a particle beam generator installed on the first floor and configured to generate a particle beam, a first transport system configured to transport a particle beam from the particle beam generator to a first irradiation system in a first treatment room, and a second transport system configured to transport a particle beam to a second irradiation system in a second treatment room, branched from the first transport system, via a second floor. The second transport system has a first bending magnet that bends a particle beam to the direction of the second floor different from the installation surface of the particle beam generator. The building has a shielding wall configured to shield the first floor and the second floor and the second transport system is provided penetrating the shielding wall.