The invention relates to a tracheal cannula inner tube for inserting into a tracheal cannula outer tube of a tracheal cannula for inserting into a tracheal stoma. The aim of the invention is to allow a free rotatability between the tracheal cannula inner tube and a component to be coupled to said tube in the direction of the spatial axis -X-X- so that for example a respiratory tube connected to the tracheal cannula inner tube can be vented and prevented from rotating and a high mechanical stability of said connection is maintained even under prolonged stress. This is achieved in that the tracheal cannula inner tube is made of a tubular cannula (1) with a first opening (21) at a first free end (2) and a second opening (31) at a second free end (3), said cannula (1) having an arch-shaped curved region (4) between the two free ends (2 and 3). The curved region (4) transitions into a conically expanding tubular region (5) at the first free end (2), and a straight tubular region (6), the diameter of which is greater than the diameter of the curved region (4), directly adjoins the expanding tubular region. A sleeve-shaped adapter piece (7), which is rotatably mounted about the axis -X-X- by 360° and in which the outer surface of the straight tubular region (6) has a circumferential groove (61), is attached to the expanding tubular region, and a circumferential bead (71) of the inner surface of the adapter piece (7) is embedded into said groove so as to fit accurately such that a friction bearing guided by the groove (61) and the bead (71) is formed between the outer surface of the straight tubular region (6) and the inner surface of the adapter piece (7).
