Abstract: An electromagnetic wave energy absorbing material for use in a solar energy industry, which absorbs effectively the energy of an electromagnetic wave such as the sunlight, is disclosed. This energy absorbing material comprises an aluminum material such as an aluminum simple substance and an aluminum alloy having a microporous aluminum oxide layer having a thickness of 0.1-1.4 .mu.m on its surface, and 0.05-1.5 g/m.sup.2 of at least one of elements selected from the group consisting of cobalt, silver, lead, molybdenum, copper, chromium, selenium, silicon, germanium, iron, manganese, nickel, zinc, tin and palladium is deposited in the micropores of the microporous aluminum layer.