The invention provides a neutron capture therapeutic device. The neutron capture therapeutic device can conduct proper treatment in a situation that a current value generated during transmission of a charged particle beam decreases. The neutron capture therapeutic device 1 has: a first current measurement part (11) for measuring the current of a charged particle beam (P), and a second current measurement part (32) for measuring the current of a charged particle beam (P) which is closer to a downstream side than the first current measurement part (11). According to the structure, in a situation that the current value of a charged particle beam (P) occurred between the second current measurement part (32) and the first current measurement part (11) decreases, a difference is generated between a first current value and a second current value. Therefore, in a situation that the difference is larger than a threshold value, a controller (100) controls ejection of a charged particle beam (P) coming from an accelerator (10) and performs proper control corresponding to reduction of the current value of the charged particle beam (P). According to the device, proper treatment is conducted in a situation that a current value generated during transmission of a charged particle beam (P) decreases.
