To provide a neutron position measurement device 11 capable of improving a positional resolution.

A plurality of neutron detection elements 12 for detecting an input neutron are juxtaposed. A neutron shield body 15 having a neutron shield section 16 for shielding a neutron and a neutron pass-through section 17 for allowing a neutron to path therethrough as a slit 18 is provided at a neutron incident face side of the neutron detection elements 12. A neutron passing through the slit 18 of the neutron shield body 15 is detected by means of the neutron detection elements 12 by moving the neutron detection elements 12 for every width of the slit 18. It is possible to obtain the positional resolution having a degree equal to the width of the slit 18 of the neutron shield body 15.