A reduced pressure or pressurizing pump is provided which can be used in a wide variety of fields of foods, pharmaceuticals, medical treatment, agriculture, healthcare equipment, room air conditioning, combustion, biotechnology, and so on. By the application of the pump of the present invention, there can be materialized, for example, an oxygen enriching apparatus or a nitrogen enriching apparatus, which have the features of an oil-free structure, a small size, compactness, low vibration, low noise, long operating life, and so on. A transport groove of a viscosity pump, which exerts a force feed action on the fluid, is formed at a relative displacement interface between a rotor and a housing, and the rotor supported by a bearing capable of coping with a high-speed rotation is rotated at a high speed.