PURPOSE: To obtain an electro-magnetic wave absorbing material which shields unnecessary noise and can be used as a housing material by homogeneously dispersing the specified amounts of wollastonite and maghemite.

CONSTITUTION: In case the wollastonite and maghenite are mixed in such a ratio that maghemite is under 10pts.wt. for 100pts.wt. of sand lime stone, sufficient electro-magnetic wave absorbing effect cannot be obtained and in case the amount of maghemite exceeds 300pts.wt., improvement of such effect is not observed and reduction of weight cannot be realized. Therefore, the 100pts.wt. of wollastonite and 50W300pts.wt. of maghemite are mixed homogeneously. When baked under the oxidation ambient, ironhydroxide of the γ type oxide changes to non-magnetic α type ironoxide. Therefore it is baked under the non-oxidation ambient with a temperature range, for example, of 800W1,200°C. Thereby, an electromagnetic wave absorbing material which can shield unwanted noise and is suited as a housing material can be obtained.