To provide an apparatus of measuring a neutron intensity distribution for discriminating a gamma ray or the like of a background and measuring images of neutrons by a simple apparatus composition.

The apparatus of measuring neutron intensity distribution combines a scintillator 3 for generating fluorescence by neutron irradiation and a position detection photomultiplier 4 of a structure taking out output signals Vx1, Vx2, Vy1 and Vy2 from both ends of respective X and Y directions. A signal processor 5 discriminates the neutrons from the other particles by pulse width of the output signals and calculates a neutron irradiation position from a difference between intensity ratios of each signal or the pulse widths.