A light weight nasal respiratory mask system securing airtightness of a mounting section between a nasal mask and a frame is provided.A nasal respiratory mask system contacting the face of a user to supply respiratory gas under positive pressure to the nose of a use and comprising at least a nasal mask, a frame and a retention wire, in which the nasal mask is a tubular member composed of a face contacting section constructed from an elastic body at one end of an opening and a frame mounting section constructed from an elastic body at the other end of the opening, the frame is a molded part with an internal space capable of communicating between a hose to supply positive pressure gas and the nasal mask and has a mechanism connectable with the hose to supply positive pressure gas and a nasal mask mounting section allowing the nasal mask to mount on periphery thereof, the frame mounting section of the nasal mask is mounted to cover from the outside the nasal mask mounting section of the frame, and at least part of the retention wire has a structure to tighten the frame mounting section of the nasal mask to the side of nasal mask mounting section of the frame.