Abstract: The invention relates to equipment for growing a thin film onto a substrate. The equipment suited to implement the invention comprises a reaction space having a reaction chamber therein into which a substrate is placed and is subjected to alternately repeated surface reactions of at least two vapor-phase reactants for the purpose of forming a thin film. The equipment further comprises recesses/openings communicating with the reaction space to form gas inflow and outflow channels. The reactants are fed in the form of vapor-phase pulses repeatedly and alternately into the reaction space through the inflow channels, each reactant separately from its own source. The vapor-phase reactants are brought to react with the surface of the substrate for the purpose of forming a solid-state thin film compound on said substrate. The gaseous reaction products and possible excess reactants are removed in gas phase from the reaction space via the outflow channels.