The performance of a novel DMFC that uses a porous carbon plate as a support was investigated. The novel DMFC is a passive type and generates power by sucking the methanol solution through the porous body by osmotic action and breathing air by natural diffusion and convection. The i-V performance measured at different methanol concentrations revealed a higher performance at methanol concentration as high as 17 M suggesting that the porous carbon plate provided a function of controlling the methanol crossover. Hence, the methanol crossover for MEA with the porous carbon plate was evaluated and was compared with that for the conventional MEA. It was confirmed that the methanol crossover was reduced by the porous carbon plate. Mass transport controlled by the porous plate was considered as a mechanism for the reduction in the methanol cross over.