PURPOSE: To obtain the manufacturing method of a porous ferrite sintered body which is applied mainly to a building or the like and which is provided with a radio-wave absorption capability.

CONSTITUTION: When a ferrite sintered body is manufactured of a ferrite powder, an auxiliary agent in a very small quantity (a silical sol aqueous solution or ethoxy silane is proper) is added in order to enhance the sintering property of the ferrite powder, this mixture is molded under a low molding pressure 2 (500kg/cm2 or lower) at 1/2 or lower of an ordinary pressure, and a molded body is heated and fired at a temperature of about 1200°C. Thereby, a porous ferrite sintered body at a porosity of 5 to 20% can be manufactured. (In conventional cases, a ferrite sintered body which is porous was not obtained).