Cycloalkylcarbonylamino acid derivatives, which are raw material intermediates of a novel cycloalkane carboxamide derivative that selectively inhibits cathepsin K, and a production process thereof, are provided.A cycloalkylcarbonylamino acid derivative represented by the following general formula (I), or a pharmaceutically acceptable salt thereof: (wherein, R1 and R2 represent alkyl groups, alkenyl groups, alkynyl groups, aromatic hydrocarbon groups, heterocyclic groups or the like, and ring A represents a cyclic alkylidene group having 5, 6 or 7 carbon atoms).