PROBLEM TO BE SOLVED: To provide a compact particle beam treatment apparatus.SOLUTION: A particle beam treatment apparatus 100 includes: a synchrotron 400; and a beam transport device 500, the transport device 500 is set with two or more inclined set deflection parts, and inclinedly linear parts are formed between the inclined deflection parts. By generating a dispersion function in the inclined linear part, size of an opening part of an electromagnet installed in the linear part is reduced to suppress power consumption.