This invention provides a particle beam therapeutic apparatus having a rotary gantry (10) which is configured to rotate an irradiation device (4) around a rotation axis (XR) and to cause the irradiation device (4) to irradiate an object with particle beam (B). The rotary gantry (10) is provided with an entrance side deflection electric magnet (1) having a deflection path guiding the particle beam (B) which is supplied along a rotation axis (XR) and deflects in a radial direction to the irradiation device (4), and a straight forward path (1s) along which the supplied particle beam (B) passes straight forwards. A track correction device (5, 6) having two position sensors (5) disposed on two sides of the rotation axis (XR), in which the entrance side deflection electric magnet (1) is interposed, is provided to correct the track of the particle beam.一種粒子射線治療裝置，係具有以使照射裝置(4)在旋轉軸(XR)的周圍旋轉，而對照射對象照射粒子射線(B)之方式構成之旋轉支架(10)者，其特徵在於：在旋轉支架(10)設置有：偏向電磁鐵(1)，該偏向電磁鐵係具有用以將沿著旋轉軸(XR)所供給之粒子射線(B)予以偏向而引導至照射裝置(4)之偏向路徑(1c)，以及可與偏向路徑(1c)自由切換之用以使所供給之粒子射線(B)直線前進之直線前進路徑(1s)；且包括：軌道修正裝置(5、6)，係具有隔著偏向電磁鐵(1)而配置於旋轉軸(XR)方向的兩側之二個位置感測器(5)。
