A quick-release coupling structure between a gas delivery tube and a respiratory mask includes a connecting member assembled to the respiratory mask and a pipe-end joint detachably coupled to the connecting member. The connecting member has two bendable tongues each having a protuberance formed on an outer surface thereof. The pipe-end joint has two sockets for receiving the tongues, and the sockets are provided with resilient members that press upon the tongues and can resiliently retract. The pipe-end joint has two retaining recesses at the sockets for retaining the protuberances. When the pipe-end joint is combined with the connecting member, the protuberances are retained by the retaining recesses. When the resilient members are pressed inward, the tongues retract and the protuberances leave the retaining recesses, so the pipe-end joint can be easily detached. Thereby, easy attachment and detachment between the gas delivery tube and the respiratory mask can be achieved.
