To develop a direct methanol fuel cell (DMFC) which can directly use high concentration of methanol, a novel passive DMFC employing a perforated metal sheet, of which the open ratio and the pore diameter were regularly controlled, between the anode electrode and methanol tank were proposed. The effect of the open ratio and the pore diameter of the perforated metal sheet on the power generation characteristics of the passive DMFC were investigated on the basis of the power generation experiment at several methanol concentrations. Methanol crossover was controlled by decreasing the open ratio to less than 1%, therefore, a high concentration of methanol could be used effectively. The methanol transfer coefficient through the metal sheet increased with increasing the open ratio up to 1%. However, when the open ratio was over 3%, the methanol transfer coefficient was nearly constant, and the control of the methanol crossover was incapable. Such effect of the open ratio on the methanol transfer coefficient could be explained by spreading the methanol solution on the surface of the metal sheet from the pore with a certain distance. The pore diameter was hardly affected the transfer coefficient.