A charged-particle beam therapy apparatus includes: an accelerator configured to accelerate a charged particle and emit a charged-particle beam an irradiation unit configured to irradiate an irradiated body with the charged-particle beam using a scanning method and a control unit. The control unit stores a control pattern of the apparatus during one treatment. An irradiation interruption time for which the irradiation of the irradiated body with the charged-particle beam by the irradiation unit is interrupted and an irradiation time for which the irradiation unit irradiates the irradiated body with the charged-particle beam are set in the control pattern. The sum of the irradiation interruption times during one treatment is set to be shorter than the sum of the irradiation times during one treatment.
