There is provided a neutron capture therapy device which irradiates a patient with a neutron beam. The neutron capture therapy device includes a cyclotron configured to emit a charged particle beam a target, a scanning electromagnet, and the like configured to generate a neutron beam by being irradiated with a charged particle beam a current monitor configured to detect a current value of a charged particle beam with which the target is irradiated and a gamma ray detection unit and a radiation dose calculation section configured to detect a radiation dose of a gamma ray which is generated from the target in response to irradiation of the charged particle beam.本發明提供一種中子捕捉療法裝置,其能夠謀求中子束照射精確度的提高。本發明是向患者(50)照射中子束(N)之中子捕捉療法裝置(1),其具備:迴旋加速器(2),其射出帶電粒子束(R);標靶(7)以及掃描電磁鐵(6)等,其藉由被照射帶電粒子束(R)而生成中子束(N);電流監視器(5),其檢測照射於標靶(7)之帶電粒子束(R)的電流值;及λ射線檢測部(11)以及劑量計算部(21),檢測藉由帶電粒子束(R)的照射而從標靶(7)產生之λ射線的劑量。1‧‧‧中子捕捉療法裝置2‧‧‧迴旋加速器3(M)‧‧‧射束導管(中子束生成部)4‧‧‧四極電磁鐵5‧‧‧電流監視器6‧‧‧掃描電磁鐵7(M)‧‧‧標靶(中子束生成部)8‧‧‧減速劑8A‧‧‧第1減速劑8B‧‧‧第2減速劑9‧‧‧屏蔽體10‧‧‧準直器10a‧‧‧開口11‧‧‧λ射線檢測部20‧‧‧控制部21‧‧‧劑量計算部22‧‧‧照射控制部23‧‧‧錯誤判定部50‧‧‧患者R‧‧‧帶電粒子束N‧‧‧中子束
