An object of the present invention is to provide a process capable of producing cycloalkanol and/or cycloalkanone with a favorable selectivity by oxidizing cycloalkane with a favorable conversion.Cycloalkanol and/or cycloalkanone are produced by oxidizing cycloalkane with oxygen in the presence of a catalyst comprising calcium oxide and a transition metal supported on the calcium oxide. The transition metal is preferably at least one metal selected from cobalt, gold, vanadium, chromium, manganese, iron, ruthenium and palladium, and more preferably cobalt or gold.