Provided is a crystal of (R)-2-[[[3-methyl-4-(2,2,2-trifluoroethoxy)-2-pyridinyl]methyl]sulfinyl]-1H-benzimidazole showing an X-ray powder diffraction pattern having characteristic peaks at interplanar spacings (d) of 10.06±0.2, 8.70±0.2, 6.57±0.2, 5.59±0.2 and 4.00±0.2 Angstroms. The present invention provides a stable antiulcer drug superior in the absorbability.