There is disclosed a thinner-layered radio wave absorber having high absorption performance for a high frequency electromagnetic wave. The radio wave absorber, even when having a magnetic layer of not more than 1 mm in thickness, achieves satisfactory absorption characteristics for the high frequency electromagnetic wave by adopting a structure that a conductor is fixedly attached to a face opposite to an electromagnetic-wave incident face of the magnetic layer of single-layered structure, and also arranging the magnetic layer to have values of a real part &mgr;′ and an imaginary part &mgr;″ of complex relative magnetic permeability of the magnetic layer satisfying an expression of &mgr;″≧m&mgr;′−n (m: real number of m>0, n: real number of n≧0) outside an impedance mismatching region.