The subject of present invention is to provide a compound showing broad and excellent antibacterial effect and having excellent safety useful for the treatment and/or prevention of infection diseases, and crystal thereof.The solution mean is to provide a hydrochloride and crystal thereof as being a novel salt form of 7-[(1R,5S)-1-amino-5-fluoro-3-azabicyclo[3.3.0]octan-3-yl]-6-fluoro-1-[(1R,2S)-2-fluorocyclopropan-1-yl]-1,4-dihydro-8-methyl-4-oxoquinoline-3-carboxylic acid and crystal thereof.本發明之課題在於提供一種顯示廣泛的優良抗菌作用，且具備優良的安全性之有用於作為感染性疾病的治療及/或預防藥的化合物的鹽及其結晶。解決手段為：提供作為7-[(1R,5S)-1-胺基-5-氟-3-氮雜雙環[3.3.0]辛烷-3-基]-6-氟-1-[(1R,2S)-2-氟環丙烷-1-基]-1,4-二氫-8-甲基-4-酮基喹啉-3-羧酸的新穎鹽形態及其結晶之鹽酸鹽及其結晶。
