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Enzymatic biofuel cells (EBFCs) based on enzyme electrocatalysts are devices to directly convert chemical energy of glucose and alcohol to electronical energy. EBFCs gather attention as a power source of wearable electronic sensor devices because they have high biocompatibility. In this paper, we report a glucose/O2 EBFC using flexible carbon cloth electrodes modified with mesoporous carbon particle, which shows high power density as high as 2 mW cm-2. Moreover, the capacity of the BFCs can be controlled by the mole number of glucose added. Porous carbon electrode was fabricated by modifying the MgO-templated mesoporous carbon (MgOC) on carbon cloth in order to enlarge surface area and to immobilize enzyme and redox mediator on electrode surface. MgOC is a kind of pore size-controlled porous carbon; mesopore size can be controlled by alternating the MgO template size. For the anode catalyst, flavin adenine dinucleotide dependent glucose dehydrogenase (FAD-GDH) from Aspergillus terreus was used. Naphthoquinones (NQ) were used as anode mediator. FAD-GDH and NQ were modified on the anode 0.19 and 1.5 mg cm-2, respectively. For the oxygen-reducing cathode, bilirubin oxidase (BOD) was used as enzyme, and 2,2’-azinobis(3-ethylbenzothiazoline-6-sulfonic acid ammonium salt) (ABTS) as mediator. BOD and ABTS were modified on the cathode 1.25 and 1.25 mg cm-2, respectively. 1.0 M phosphate buffer (pH = 7.0) was used as an electrolyte. A cellophane sheet was sandwiched between the anode and cathode as a separator. Figure 1 shows the cell power (solid lines) and cell voltage (broken lines) as a function of current density of the EBFCs. The maximum output power density of BFCs using 1,2-NQ and 1,4-NQ for anode mediators were 1.69 and 2.06 mW cm-2, receptively, because the redox potential of 1,4-NQ is more negative than that of 1,2-NQ. Figure 2 shows the cell capacity of the BFCs as a function of glucose concentration added to the cell. The capacity of the cell increased linear with an increase of the mole number of glucose. Figure 1