PURPOSE: To obtain a microwave absorbing body with a broad band, by mixing a magnetic substance with dispersion, on a absorbing body made of rubber or plastic, so that the dielectric constant of the absorbing body can be adjusted with a minimum reflection coefficient.

CONSTITUTION: In a microwave absorbing body consisting of an absorbing body 1 and a metal plate 2 provided to a surface of the body 1, a magnetic substance such as ferrite and carbonyl-iron is mixed in the absorbing body 1 with scattering with the volume ratio of ≤0.3 ferrite and ≤0.2 carbonyl-iron, and the dielectric substance which is less in the loss with ≥20 dielectric constant is mixed to the absorbing body, allowing to minimize the reflection coefficient.