The present invention relates to a direct methanol fuel cell having reduced methanol crossover, which comprises a layer of material for controlling the diffusion rate of fuel. More particularly, it relates to a direct methanol fuel cell in which the material for controlling the diffusion rate of fuel is interposed between an anode and a fuel reservoir or positioned within the fuel reservoir, and thus, the diffusion rate of methanol is reduced even when using high concentration methanol fuel, such that the injected methanol is completely reacted in a catalyst layer so as to fundamentally reduce unreacted methanol, thereby suppressing the methanol crossover phenomenon and exhibiting high power density. In the inventive direct methanol fuel cell, the diffusion rate of fuel is controlled using the fuel diffusion rate-controlling material so as to suppress the methanol crossover phenomenon, thereby increasing energy density and output density. Also, since a high methanol concentration of aqueous methanol fuel is used in the inventive fuel cell, the fuel cell can be used for a long period of time even with a small amount of fuel, and the volume of the fuel reservoir can be reduced, thus making it easy to miniaturize the fuel cell. According to the invention, the performance of all kinds of direct methanol fuel cells can be improved and the fuel cells can be used as electric power sources for small-sized portable electronic products, such as portable phones, PDAs, and notebook computers.