Provided are crystals of 3-ethyl-4-{3-isopropyl-4-(4-(1-methyl-1H-pyrazol-4-yl)-1H-imida zol-1-yl)-1H-pyrazolo[3,4-b]pyridin-1-yl}benzamide which are stable and have excellent oral absorbability. The crystals are II-form crystals of 3-ethyl-4-{3-isopropyl-4-(4-(1-methyl-1H-pyrazol-4-yl)-1H-imida zol-1-yl)-1H-pyrazolo[3,4-b]pyridin-1-yl}benzamide which are characterized by giving an X-ray powder diffraction spectrum which has characteristic peaks at at least three diffraction angles (2?±0.2º) selected from among 7.7º, 8.0º, 11.1º, 12.5º, 12.9º, 15.2º, 15.8º, 17.2º, 19.0º, 22.5º, 26.1º, and 27.4º.Se proporcionan cristales de 3-etil-4-{3-isopropil-4-(4-(1-metil-1 H-pirazol-4-il)-1Himidazol-1-il)-1H-pirazolo[3,4-b]piridin-1-il}b enzamida que son estables y muestran excelente capacidad de absorción oral; los cristales son cristales de Forma II de 3-etil-4-{3-isopropil-4-(4-(1-metil-1H-pirazol-4-il)-1H-imidazol- 1-il)-1H-pirazolo[3,4-b]piridin-1-il}benzamida que muestran un espectro de difracción de polvo de rayos X que tiene al menos tres picos de difracción característicos en ángulos (2q ± 0.2°) seleccionados del grupo que consiste en 7.7°, 8.0°, 11.1°, 12.5°, 12.9°, 15.2°, 15.8°, 17.2°, 19.0°, 22.5°, 26.1°, y 27.4°.