To provide a cleaning method and a cleaning apparatus which can remove mold dirt attached to the surface of a matter to be cleaned sufficiently in a short period of time.

The cleaning apparatus for cleaning a die surface of a lower die 1 is provided with a light source 11 with an excimer lamp 7, a delivery pipe 12 to deliver gas containing oxygen into a space between the die 1 and the light source 11, and a cylinder 15 filled with pure oxygen(O2) connected to the pipe 12 through a feed pipe 13 and a solenoid valve 14. Excimer light 10 projected from the lamp 7 cuts off a chemical bond such as mold dirt 5 attached to a die surface, thereby decomposing a part of the bond into carbon 17 and hydrogen (not shown), or the part of the bond is absorbed by oxygen molecules 18 and decomposed into active oxygen atoms(O*) 19 and ozone(O3) 20. As a result, the carbon 17 and hydrogen react with the oxygen atoms 19 to produce CO2 and H2O, which are volatilized to remove the dirt 5.