A nasal respiratory mask system comprising: a nasal mask (11) that is firmly attached to a user's face and serves as a means to drive positive pressure breathing gas to the user's nose, a structure (12) for keeping the nasal mask (11) in a predetermined position, and a harness (13) that is mounted on the head to hold the nasal mask firmly to the face； wherein, the harness (13) comprises a strap (13a) of the harness to adjust the length of the harness, the strap (13a) of the harness comprises, at the tip thereof, a fastening element (14) of the harness that serves as means of connection / disconnection with the structure (12), the structure (12) comprises a closure (15) of the fastener that is applied with the fastener (14) of the harness, characterized in that: the fastener (15) of the clamping element comprises an axially symmetrical guide (15b) whose axis is the direction of insertion of the clamping element (14) of the harness, the shape of the guide is a slit that is in the form of a spindle or cone shape, and the element clamp (14) of the harness has a protruding V-shaped part approximately adapted to the slit, and because: the guide (15b) has a shape that allows the deviation during insertion of the harness clamp in the direction of rotation, whose axis is the direction of in serción of the element of subjection (14) of the harness and in a plane perpendicular to the axis.Un sistema de máscara respiratoria nasal que comprende: una máscara nasal (11) que está firmemente unida a la cara de un usuario y sirve como medio para conducir el gas de respiración de presión positiva a la nariz del usuario, una estructura (12) para mantener la máscara nasal (11) en una posición predeterminada, y un arnés (13) que está montado en la cabeza para sujetar la máscara nasal firmemente a la cara； en donde, el arnés (13) comprende una correa (13a) del arnés para ajustar la longitud del arnés, la correa (13a) del arnés comprende, en la punta del mismo, un elemento de sujeción (14)
