The problem to be solved is to produce, at high yields with high purity, anhydrous crystals of a compound represented by formula (1) that is an important intermediate for preparation of FXa inhibitor compound (X) or a pharmacologically acceptable salt thereof, or a hydrate thereof. The solution thereto is an industrial preparation process that provides, with high purity, anhydrous crystals of a compound represented by the following formula (1), which is an intermediate for the production of FXa inhibitor compound (X) or a pharmacologically acceptable salt thereof, or a hydrate thereof, wherein Boc represents a tert-butoxycarbonyl group.