To obtain the oxygen enriching method and equipment which can be operated without producing excessive oxygen by balancing the quantity of necessary oxygen for the waste melting furnace and the quantity of produced oxygen by an oxygen generating unit with each other.

In oxygen-enriching by oxygen from a pressure swing type oxygen generating unit in a waste melting furnace for subjecting waste to thermal decomposition melting by blowing oxygen-enriched air into a waste melting furnace 16 from a tuyere, the quantity of generated oxygen is controlled by controlling according to the amount of oxygen required by the waste melting furnace 16 the quantities of passing-through gases of each of a raw material blower 4 for feeding air into adsorption tanks 1a and 1b, a vacuum pump 7 for taking out adsorbed nitrogen gas from the adsorption tanks 1a and 1b and a booster blower 11 taking out the oxygen gas from a pressure equalizing tank 10.