A
crystal of 7-((3R,5S)-1-acryloyl-5-methylpyrrolidin-3-yl)-4-amino-6-(cyclopropylethynyl)-N—((R)-1-phenylethyl)-7H-pyrrolo[2,3-d]
pyrimidine-5-
carboxamide (compound (I)), and a
crystal thereof with an acid (salt
crystal or co-crystal) are provided.There are provided: a type II crystal of compound (I) with
fumaric acid, having characteristic peaks at three or more
diffraction angles (2θ±0.2°) selected from 5.5°, 6.8°, 9.3°, 13.4°, 15.3°, 16.3°, 18.5°, 19.8°, 22.0°, and 24.5° in a
powder X-
ray diffraction spectrum;a (free-form) type II crystal of compound (I) having characteristic peaks at three or more
diffraction angles selected from 8.3°, 14.8°, 17.3°, 18.0°, 19.1°, 20.3°, 21.0°, 22.5°, 23.0°, and 26.2° in a
powder X-
ray diffraction spectrum;a (free-form) type I crystal of compound (I) having characteristic peaks at three or more diffraction angles selected from 9.9°, 11.7°, 13.2°, 17.7°, 18.1°, 18.8°, and 20.8° in a
powder X-
ray diffraction spectrum;a type V crystal of compound (I) with
fumaric acid, having characteristic peaks at four or more diffraction angles selected from 6.9°, 9.4°, 10.2°, 13.7°, 21.1°, 23.6°, and 26.5° in a powder X-ray
diffraction spectrum; anda type I crystal of compound (I) with
fumaric acid, having characteristic peaks at four or more diffraction angles selected from 6.4°, 10.3°, 12.8°, 15.0°, 20.7°, 23.4°, and 26.6° in a powder X-ray diffraction spectrum.