An oxygen respirator with safety and simple handling, comprising a body, a small portable-type oxygen cylinder or oxygen generator mounted on the body, a mask, a first hose transferring oxygen from the body to the mask, a tank member mounted on the body for receiving exhalation, a second hose transferring exhalation from the mask to the body, and a carbon dioxide absorbing material charged in the body for removing carbon dioxide from exhalation sent back from the mask to the body. During emergency and evacuation for example in fire, thus, oxygen is transferred to the mask by removing a trigger or the like. The respirator also enables the reuse of exhalation for respiration. Despite of the small size, therefore, the respirator can protect a user from risks such as suffocation for a relatively long period of time.