To improve the positional resolution in the Y direction and to obtain the neutron detector of simple structure capable of being esily fabricated.

A high-voltage electrode 1 and an internal partition plate 3 as a cathode are alternately arranged in a housing 10 and integrally sealed along with a neutron-sensitive material 2 to constitute a neutron detector 100 of this invention. As a result, the structure is simplified, and the detector is easily produced. Further, since the sealing pressure of the neutron-sensitive material 2 is skilfully uniformized in the housing 4, the pressure is not exerted on the partition plate 3. Consequently, the partition plate 3 can be thinned, and the positional resolution in the Y direction is improved.