Abstract: A channel burner for heating up flowing gas, accommodated inside the channel (1) that conveys the gas and provided with an airbox (2) and a combustion space (3) separated by a burner floor (5). The airbox communicates with an air intake (6) and the burner floor is provided with air-outlet openings in the form of slots (15) in the vicinity of the wall (4) of the combustion space. A gas-supply pipe (7) extends through the airbox and communicates with one or more gas nozzles (12) with bores (13) that open into the combustion space. The outlet cross-section of the slots is beside the bores. The outlet cross-section of the slots is remote from and downstream of the bores in terms of the flowing gas. The slot extends toward the wall of the combustion space. The ratio of the width s of the slot to the width 1 of the combustion space ranges from 0.01:1 to 0.1:1 at the level of the outlet cross-section of the slots.