In this study, we are doing R&D for directional dark matter search with nuclear
emulsion. First of all, higher resolution nuclear emulsion with fine silver halide
crystals was developed in the production facility of emulsion at Nagoya university, and we
confirmed that it can detect the expected nuclear recoil tracks. The readout of submicron
tracks was required the new technology. We developed the expansion technique, and could
readout the signal by shape analysis with optical microscopy. The two dimensional angular
resolution is 36 degrees at the original track length of range from 150 nm to 200 nm with
optical microscopy. Finally we demonstrated by using recoiled nuclei induced by 14.8 MeV
neutron, and confirmed the technique. Moreover, we developed the X-ray microscope system
with SPring-8 as final check with higher resolution of selected candidate tracks with
optical microscopy. The angular resolution was improved from 31 degree with optical
microscopy to 17 degree with X-ray microscopy at the track length of range from 150 nm to
250 nm. We are developing the practical system and planning for start of the test running
with prototype detector.