A nozzle head and an apparatus for subjecting a surface of a substrate to successive surface reactions of at least two precursors according to the principles of atomic layer deposition, the nozzle head includes a nozzle head body, a nozzle head output face and gas channels for transporting gas. The nozzle head further includes a first through hole through at least two of the two or more nozzles and a first tube having a tube wall and being fitted into the first through hole, said first tube including gas conduits provided in the tube wall for providing a fluid communication between the first tube and the gas channels in connection with the two or more nozzles.