The present invention relates to a nasal respiratory mask system comprising: a nasal mask that is tightly attached to the face of a user and serves as means for leading positive-pressure breathing gas to the nose of the user, a frame to keep the nasal mask at a predetermined position, and a headgear that is mounted on the head in order to attach the nasal mask tightly to the face; wherein, the headgear comprises, on the tip thereof, a headgear strap for adjusting the length of the headgear, the headgear strap comprises a headgear fastener that serves as means for connection/disconnection with the frame, the frame comprises a fastener catch that engages with the headgear fastener, and the fastener catch comprises an axisymmetric guide whose (rotation) axis is the insertion direction of the headgear fastener. The present invention provides a nasal respiratory mask system with which a headgear can be easily connected at the beginning of wearing, twisting of the headgear during wearing is prevented, and disassembly upon daily washing is easy.