The present invention is constituted with crystal of 2-amino-3-cyano-4-methyl-5-(2-fluorophenyl)pyrrole, which show diffraction peaks at diffraction angles (2.theta..+-.0.2 degree) of 10.3 degree, 14.3 degree, 15.5 degree, 15.9 degree, 25.1 degree and 25.7 degree in a powder X-ray diffraction spectrum, and also show absorption peaks at wavenumbers (cm.sup.-1, .+-.0.2%) of 3373, 3322, 2201, 762, 687 and 640 in an infrared absorption spectrum.The crystal of the present invention is superior in stability and is useful as a pharmaceutical bulk.