A microbial fuel cell attracts attention as a system producing electric energy. Until now Wakisaka et al have researched on glucose fuel battery using baker's yeast. The fuel cell consists of anode and cathode parts separated by a cation specific membrane, and electrons are generated by glucose oxidation by yeast in the anode part. The electrons are transferred to the electrode (carbon cloth) from yeast cells by mediators. The constitution of the suitable battery has been examined using commercial baker's yeast. Here Saccharomyces cerevisiae laboratory yeast (BY4741 strain) was used to construct the suitable yeast using genetic recombination technology for the battery in the future, and culture condition of yeast and the suitable battery condition (pH of the anode solution and yeast amount) were examined. As a result the output of the level same as the baker's yeast was obtained, and it was shown that a fall of the pH in the anode affected the output. To clarify the detail of electron generation in yeast cell, the effect of respiratory inhibitors on the electron generation and time courses of glucose consumption and ethanol concentration in the battery were examined. Many electrons were produced at the time of ethanol production (early period of electron generation). Electrons were also produced in the time when ethanol production was not detected (last period of electron generation). These results suggest that electrons are produced in both processes of fermentation and respiratory of yeast.