A respirator mask device includes a frame unit, a mask shell connected pivotally to the frame unit, a mask cushion secured to the mask shell, an adjusting unit operable for adjusting relative position between an upper end of the mask shell and the frame unit, two connecting pieces disposed respectively on left and right sides of a lower end of the frame unit and connected pivotally to the mask shell, two first engaging members disposed respectively on the left and right sides of the lower end of the extension frame, and a head strip unit. The head strap unit includes a strap body, and two second engaging members disposed on the strap body and connected respectively and removably to the first engaging members.
