A charged particle beam treatment apparatus includes: an accelerator configured to emit a charged particle beam by accelerating charged particles； an irradiation portion configured to irradiate an irradiation object with the charged particle beam through a scanning method； a transport line configured to transport the charged particle beam emitted from the accelerator to the irradiation portion； an energy adjusting portion configured to adjust energy of the charged particle beam； an electromagnet which is provided in the irradiation portion or the transport line； an electromagnet power source which is connected to the electromagnet； and a control portion. Semiconductors are connected between the electromagnet power source and the electromagnet in series. When switching a layer of the irradiation object to be irradiated with the charged particle beam, the control portion reduces the energy of the charged particle beam by controlling the energy adjusting portion and increases a resistance of the semiconductors.
