Provided are crystals of 3-ethyl-4-{3-isopropyl-4-(4-(1-methyl-1H-pyrazol-4-yl)-1H-imidazol-1-yl)-1H-pyrazolo[3,4-b]pyridin-1-yl}benzamid which are stable and show excellent oral absorbability. The crystals are Form II crystals of 3-ethyl-4-{3-isopropyl-4-(4-(1-methyl-1H-pyrazol-4-yl)-1H-imidazol-1-yl)-1H-pyrazolo[3,4-b]pyridin-1-yl}benzamide showing an X-ray powder diffraction spectrum having at least three characteristic diffraction peaks at angles (2¸ ± 0.2°) selected from the group consisting of 7.7°, 8.0°, 11.1°, 12.5°, 12.9°, 15.2°, 15.8°, 17.2°, 19.0°, 22.5°, 26.1°, and 27.4°.
