A particle beam treatment apparatus includes: a gantry configured to axially rotate in a state where an irradiation port for a beam is fixed to a body of the rotating gantry; a moving floor that is provided inside the gantry, is configured by annually connecting a plurality of plates with each other in a freely bendable manner, accommodates at least a part of a bed fixed from a stationary system, and rotates together with the gantry in a state of causing the irradiation port to penetrate the moving floor; a cable configured to be connected to a device fixed to the moving floor and be wired to outside of the gantry in a state of passing through the gantry; and an adjuster configured to adjust length of the cable wired inside the gantry when the gantry axially rotates.