Mask and head-mounted display device

According to the mask and the head-mounted display device, the overall thickness and hardness of the mask can be adjusted through inflation and deflation adjustment, and universality and wearing comfort are improved. The mask comprises a shell and a supporting piece, a closed annular air cavity is defined by the inner side face, the outer side face, the face attaching face and the connecting face of the shell, and an automatic inflation and deflation nozzle is arranged on the outer side face. The annular air cavity is filled with the supporting piece, and the supporting piece is made of a soft rebounding material. Main parts of a shell of the mask are all made of soft materials, a closed annular air cavity is formed in the shell, a soft rebounding supporting piece is arranged in the air cavity and serves as an internal framework of the mask, and meanwhile an automatic inflation and deflation nozzle used for inflating and deflating the annular air cavity is arranged on the outer side face of the mask. The auto