To stabilize the air flow forming an air curtain, a thermotherapy device (1) is provided with air outlet ducts (3) extending at the edge of the reclining surface (2) and with two opposite limiting walls (6, 6′). Each of the two opposite limiting walls (6, 6′) is arranged corresponding to the duct width for outflowing air. At least one limiting wall (6, 6′) of at least one air outlet duct (3) is provided with a cylinder (5, 5′) extending in the direction of flow of the air outlet duct (3) and in parallel to the reclining surface (2) at the discharge-side end, wherein the cylinder (5, 5′) has a diameter corresponding to 0.005 to 0.2 times the duct width of the air outlet duct (3). According to a variant, at least one limiting wall (6, 6′) of at least one air outlet duct (3) is provided with at least one inner wall (81, 82, 83, 84) forming a nozzle at the discharge-side end. The distance between the limiting wall (6, 6′) and the inner wall (81, 82, 83, 84) forming a nozzle with the limiting wall (6, 6′) is 0.01 to 0.5 times the duct width of the air outlet duct (3).
