A neutron capture therapy system includes an accelerator for accelerating charged particles to generate a charged particle beam, a beam transmitting device, and a neutron beam generating device. The neutron beam generating device further includes a first, a second and a third neutron beam generating device. The beam transmitting device further includes a first transmitting device connected to the accelerator, a beam direction conversion device configured to switch a traveling direction of the charged particle beam, and a second, a third and a fourth transmitting device that respectively transmit the charged particle beam from the beam direction conversion device to the first, the second and the third neutron beam generating device, wherein two of the first, the third and the fourth transmitting device define a first plane, a first and a second transmitting device define a second plane, and the first plane is different from the second plane.