We prepared a new IPN composed of pH-sensitive poly(ã-glutamic acid) (PGA) and temperature-sensitive poly(N-isopropylacrylamide) (PNIPAM), both of which include amide groups and are expected to interact each other via hydrogen bonding. First, ethylene glycol-di-glycidyl ether was added to aqueous solution of PGA to form PGA gel. Then NIPAM and crosslinker were penetrated into PGA gel. The mixture was UV irradiated to polymerize NIPAM in-situ at room temperature. The stimuli-responsiveness and mechanical properties of IPN thus obtained were measured. IPN gel exhibited much sharper temperature response than simple PNIPAM gel when suitable ratio of PNIPAM to PGA was chosen. The IPN gel also responded to pH change. The IPN had higher mechanical strength by more than 60 times than simple PGA or PNIPAM. IPN microgels were obtained when PGA gel was prepared in diluted solutions of PGA. The response of IPN microgels to the change in environmental conditions was much faster than that of bulk gels.