A method of manufacturing a radio frequency accelerator in which charged particles emitted from a first stage linear accelerator (2) are incident and accelerated by a second stage linear accelerator (3), in each of the second stage linear accelerators (3) Phase charged particle beams from a second stage linear accelerator (3) in a range of total high frequency power that is wider than the maximum allowable range among the allowable ranges of all the high frequency powers determined on the basis of the phase acceptance with respect to incident charged particles of the charged particle beam , The value of the power distribution ratio R of the high frequency power to be supplied to the second stage linear accelerator (3) of the power distribution device (7) and the value of the power distribution ratio R of the high frequency power from the outlet of the first stage linear accelerator (2) And the value of the ratio L / of the length L of the matching section (8) to the entrance of the linear accelerator (3) and the angular frequency of the high frequency power.1段目の線形加速器(2)から出射される荷電粒子を入射して2段目の線形加速器(3)で加速する高周波加速器の製造方法において、2段目の線形加速器(3)における、各位相の入射荷電粒子に対する位相アクセプタンスに基づいて決定される前記全高周波電力の許容範囲のうちの最大許容範囲よりも広い全高周波電力の範囲において、2段目の線形加速器(3)から荷電粒子ビームが出射されるように、電力分配装置(7)の2段目の線形加速器(3)に供給する高周波電力の電力分配率Rの値と、1段目の線形加速器(2)の出口から2段目の線形加速器(3)の入口までのマッチングセクション(8)の長さLと高周波電力の角周波数ωとの比L/ωの値と、を設定する工程を含むようにした。
