A medical neutron source, comprising - a nuclear reactor, with a core formed by a parallelepiped-shaped housing having a front, rear and two side walls, as well as a lid and a bottom, reflector of neutrons, covering the core from the rear, side, top and bottom sides and including the rear, side, upper and lower reflectors, located on the housing of the upper supporting and lower distancing grids, fuel rods, the upper shanks of which are fixed stationary to the upper support grid with the possibility of vertical movement of the lower shanks under temperature expansion fuel rods, channels located on the lid of the housing for the placement of CPS controls, located on the housing the supply branch pipe and the discharge branch pipe of the heat-stabilized primary circuit coolant, partitions separating the internal volume of the housing to ensure the washing over of fuel rods and channels for the placement of CPS controls by the coolant; - a collimator with a conical hole made of a material having a large scattering cross-section and a large atomic mass, - a neutron filter placed in the conical hole of the lead collimator in such a way that the larger diameter of the conical hole is adjacent to the front wall of the shell of the core of the reactor, - protection covering the neutron reflector and the collimator and subdivided into the front, back, side, top and bottom, - channel for neutron-capture therapy, formed by a hole in the frontal protection, located coaxially with the conical hole of the lead collimator, - at least one channel for fast neutron therapy, formed by a through hole in the side protection and a side reflector, - the first movable gate for opening and closing the neutron exit channel for neutron-capture therapy, - the second movable gate for opening and closing the neutron exit channel for fast neutron therapy. - a nuclear reactor, with a core formed by a parallelepiped-shaped housing having a front, rear and two side walls, as well as a lid and a bottom, reflector of neutrons, covering the core from the rear, side, top and bottom sides and including the rear, side, upper and lower reflectors, located on the housing of the upper supporting and lower distancing grids, fuel rods, the upper shanks of which are fixed stationary to the upper support grid with the possibility of vertical movement of the lower shanks under temperature expansion fuel rods, channels located on the lid of the housing for the placement of CPS controls, located on the housing the supply branch pipe and the discharge branch pipe of the heat-stabilized primary circuit coolant, partitions separating the internal volume of the housing to ensure the washing over of fuel rods and channels for the placement of CPS controls by the coolant; - a collimator with a conical hole made of a material having a large scattering cross-section and a large atomic mass, - a neutron filter placed in the conical hole of the lead collimator in such a way that the larger diameter of the conical hole is adjacent to the front wall of the shell of the core of the reactor, - protection covering the neutron reflector and the collimator and subdivided into the front, back, side, top and bottom, - channel for neutron-capture therapy, formed by a hole in the frontal protection, located coaxially with the conical hole of the lead collimator, - at least one channel for fast neutron therapy, formed by a through hole in the side protection and a side reflector, - the first movable gate for opening and closing the neutron exit channel for neutron-capture therapy, - the second movable gate for opening and closing the neutron exit channel for fast neutron therapy.