A respiratory mask (1) comprising a mask body (2) comprising elongated arms (20) projecting away from the mask body (2), and a headgear (10) detachably secured to said elongated arms (20). At least one of the elongated arms (20) comprises at least one pin element (21). The headgear (10) comprises at least one flexible sleeve structure (12) comprising at least one traversing hole (13). The at least one of the elongated arms (20) is at least partially inserted into said at least one flexible sleeve structure (12) and said at least one pin element (21) is inserted into said at least one traversing hole (13). The invention further concerns a respiratory gas delivering assembly comprising a gas source, preferably a CPAP or BPAP device, delivering a pressurized respiratory gas, such as air under pressure, and a respiratory mask (1) according to the invention, preferably a nasal pillow mask comprising two hollow prongs (6) entering into the nostrils of the patient, when said patient wears the mask (1).
