Abstract: A surface adsorption apparatus for dissociating H.sub.2 molecules into atomic hydrogen in a vacuum vessel and adsorbing the atomic hydrogen on a sample surface is disclosed. A vacuum tube is mounted in the vacuum vessel. A nozzle is connected to the vacuum tube having a plurality of bent portions. A heating member receives electrical power from a power supply source and heats the nozzle to a predetermined temperature. A heat shielding member is located in a path of the atomic hydrogen between one end of the nozzle and the sample surface for shielding the sample surface from heat radiating from the nozzle. The H.sub.2 molecules collide with inner wall surfaces of the bent portions to be readily dissociate into the atomic hydrogen. The atomic dissociated hydrogen propagates toward the sample surface and is adsorbed on the sample surface. Since the nozzle comprises bent portions, H.sub.2 molecules frequently collide with inner wall surfaces of the nozzle to readily dissociate into atomic hydrogen. The H.sub.