The electromagnetic wave (EM) absorption properties of various particle size have been investigated in a sheet-type absorber using the Fe_73Si_16B_7Nb_3Cu_1 alloy powder. With decreasing the average particle size, the complex permeability (µ_r) and permittivity (varepsilon_r) increased and the matching frequency is shifted toward lower frequency. The fabricated EM wave absorbers showed permeability 2sim6, permittivity 17sim23 for a -325sim+400 mesh sample, and the calculated power absorption was as high as 80% in the frequency range over 2 GHz.