A fitting apparatus for connecting pipes according to the present invention includes a fitting unit which includes a first body into which a first pipe is inserted and a second body which is connected to the first body to form a pipe insertion space therein together with the first body and into which a second pipe is inserted, wherein in the first body and the second body, a first recessed groove and a second recessed groove spaced apart inward from the first recessed groove are formed along an inner circumferential surface thereof, respectively, a compression member which is provided in the first recessed groove to compress and fix the first pipe or the second pipe, and a sealing member which is provided in the second recessed groove to maintain airtightness between the fitting unit and the first pipe or between the fitting unit and the second pipe.