Two types of solar cell modules having an equal output voltage and different
sizes are used, and a plurality of solar cell modules of these two types are installed
so that they are connected in parallel. The size of a solar cell module having
two solar cell sub-modules is two times larger than the size of a solar cell module
including one solar cell sub-module. By connecting two power generating regions
of each of the solar cell sub-modules of the former solar cell module in parallel,
connecting adjacent two solar cell sub-modules in series and connecting two power
generating regions of the solar cell sub-module of the latter solar cell module
in series, an equal output voltage is obtained from both of the solar cell modules.
