On the basis of recent current measurements, we propose a new gyre system in Lake Biwa during summer. A great volume of current data was obtained with automatic current meters moored in the surface layer of Lake Biwa during 1977-1991. This data was statistically analyzed to obtain information regarding the time-averaged current velocity field. Trajectories of several drifters tracked by radar were also analyzed to explore typical surface circulation patterns. As a result, the mean surface circulation was found to consist of two large gyres, one counterclockwise and the other clockwise. The positions of these gyres differ substantially from those estimated in previous studies. The so-called Third Gyre was not clearly observed.