1 wt% Ag, Cu and Co-containing Activated Carbon Fibers(ACFs) were prepared and the pore size distributions depending on the activation condition were investigated. The burn-offs of metal-containing carbon fibers(CFs) are higher than that of non metal-containing CFs, because the metal accelerates the activation of carbon. Cobalt is better accelerator than copper and silver. Activation energies of three metal-containing CFs were 93, 141 and 175 kJ/mole, respectively, which were lower than that, 184 kJ/mole, of non metal-containing ACF. The isotherms of 1 wt% metal-containing ACFs were typical Type-I such as non metal-containing ACF. However, Co-containing ACF has mesoporous pores with hysteresis loop and rising tag at high relative pressure. Ag and Cu-containing ACFs have the average pore size of 18-20Å in spite of low activation energy, while Co-containing ACF has two mesoporous regions of 30-40Å and 200-300Å with micropores.