A nasal mask (100, 100), comprising a connector (10), a bent tube (20), a casing (30), a flexible mask casing (50), a support (60, 80) and a strap (70, 90). The bent tube (20) is connected to the connector (10), the casing (30) is connected to the bent tube (20), a plurality of protruding clamping positions (3311, 3313, 3333) and recessed fastening positions (3331) are arranged at intervals on the casing (30), at least a portion of the clamping positions (3311, 3313, 3333) and the fastening positions (3331) form at least two matching structures, the flexible mask casing (50) is arranged at the end of the casing (30) away from the bent tube (20), a cushioning structure (58) is arranged on the flexible mask casing (50), the support (60, 80) is detachably sleeved on the casing (30) and comprises a combining portion (61, 81) and a connecting portion (63) extending outwards from the combining portion (61, 81), the combining portion (61, 81) is provided with a combining hole (611, 811), and the combining portion (61, 81) of the support (60, 80) may be matched with at least one of the at least two matching structures of the casing (30) by sleeving the combining hole (611, 811) on the casing (30).
