The respiratory therapy device (1) has a channel branch connection (21) that is opened in a passage channel (7) of a mouthpiece (6). A pipe piece (22) is attached at the channel branch connection. An air-distributing element (23) is inserted in the pipe piece. A passage opening (26) is incorporated in outer circumference of the air-distributing element. An outer width of the passage opening is adjusted by a rotary mounted actuating ring.
