Abstract: It is intended to provide a novel low-molecular weight amine derivative, that is absorbed well, has low toxicity, and has an excellent human ?-tryptase inhibitory activity with extremely high selectivity, a pharmaceutically acceptable salt thereof, and a medicine containing the same as an active ingredient. The medicine of the present invention is efficacious as a prophylactic/therapeutic agent for diseases in the crisis and evolution of which are considered to be attributed to ?-tryptase, for example, respiratory diseases, allergic diseases, inflammatory bowel diseases, hyperprolliferative skin diseases, vascular edema and rheumatoid arthritis.