Disclosed are a respirator and a head-mounted protection apparatus. The respirator includes a respirator body. A breathing passage is formed in the respirator body for airflow when a user breathes. The respirator further includes a filter layer switching device and at least two filter layers of different filtering properties, and the filter layer switching device is installed on the respirator body and is configured to switch filter layers below the breathing passage according to requirements. In use of the respirator, the user can transfer a filter layer of a required performance to a region below the breathing passage using the filter layer switching device based on his requirement for air filtration.