Fast neutrons, which are neutrons with energies greater than 1 MeV, are expected to be a source of nondestructive inspection for a large-size infrastructure such as a bridge girder because of their mean free path exceeding the meter. A neutron-imaging device with 10-ns time resolution can discriminate pulsed neutrons from X-rays via time of flight. For this purpose, we require a fast-response neutron imager with large aperture and high image resolution. A neutron-imaging device with time resolution of 10 ns and aperture size of 40 cm × 60 cm was developed. It was filled with fast response liquid scintillator  in an aluminum honeycomb plate, which converts neutrons to optical light images. The scintillation light images were relayed using an optical lens and detected using a fast response image intensified CCD. The detector was tested at an electron linear accelerator (LINAC) facility in Osaka University. A short X-ray pulse (30 ps pulse duration) was generated using LINAC, and X-ray radiograph images were obtained with a 10- ns exposure time duration. The radiograph images were well attenuated within 10-ns from the X-ray injection. A high energy X-ray image and a neutron radiograph image of a 30-cm thick concrete block with iron blocks located behind it were successfully observed. This promising technique could facilitate nondestructive inspection of large concrete constructions.