In this paper, the mechanical properties of fresh concrete were evaluated by using electric arc furnace oxidizing slag(EOS) aggregate. Water-Cement(W/C) ratio was selected as 0.45 and 0.30, and the mixing amount of EOS aggregate as 0%, 50%, 100%. Experimental items of fresh concrete were slump, flow, air content, unit volume weight. As a results, As the mixing amount of EOS aggregate increased, the slump and flow increased but the air content decreased.