Particle beam treatment apparatus

A particle beam treatment apparatus comprising:

• a rotating gantry configured to axially rotate in a state Where a bed fixed to a stationary system is disposed inside the rotating gantry and an irradiation port of a beam is fixed to a body of the rotating gantry;
• a tunnel structure configured to have at least a horizontal floor surface and have an internal space in which at least a part of the bed is accommodated;
• a rotation supporter configured to cause the tunnel structure to be stationary in the stationary system independently of axis rotation of the rotating gantry by rotationally displacing the tunnel structure with respect to an inner side surface of the rotating gantry;
• a moving floor configured to be formed by bendably joining a plurality of plates to each other in an annular shape such that the internal space is continuous from the tunnel structure, and rotate together with the rotating gantry in a state where the irradiation port penetrates the moving floor;
• wherein one end of the moving floor is engaged with a first rail, which is supported by the stationary system and includes a closed track substantially matching in vertical cross-sectional shape with the tunnel structure;
• and
• another end of the moving floor is engaged with a second rail fixed to the tunnel structure, the second rail is disposed to face the first rail such that the irradiation port is interposed between the first rail and the second rail.