The present invention concerns a valve unit for a rebreather apparatus that recycles gas exhaled by a user. The valve unit includes a housing 5 with a first port for communication with a respiratory system of the user and a first inlet port 9 for breathable gas in said housing, a first exit port for exhausting gas from said housing into a flow channel, at least one separate second exit port 12 for exhausting gas form said housing 5 into an ambient environment, a second inlet port 13 for breathable gas connected to an open loop inlet valve 6 in said housing 5, and a valve body 4 in said housing 5 forming a valve for switching between two operating modes. The valve body 4 is formed as a barrel or cylinder with valve openings sealing against the housing 5, where the valve body 4 forms an internal cavity 18, alone or in combination with the housing 5, in connection with the port 10 for communication with a user. The valve 6 has an outlet in said cavity 18.