PURPOSE: To reduce an installation space for solar battery while smoothly starting and stopping a soler power generation system according to solar insulation conditions.

CONSTITUTION: An output terminal of one modules SCn out of a plurality of modules of which a solar battery 1 is formed is short-circuited by closing a relay 23, and when a condition that a short-circuit current ISC is larger than a set point ISCS is detected by a comparator CP2, a contactor 22 is closed through a switching controller 21 and a system is started, and the relay 23 is opened and a terminal short-circuit of the module SCn is released and a normal connection is resumed and the solar battery 1 is formed as a power supply device for a load. Also, when a condition that an output DC power PD of the battery is smaller than a set point PDS is detected by a comparator CP1, the contactor 22 is opened through the switching controller 21 and the system is stopped, and the relay 23 is closed and an output terminal of the module SCn is again short-circuited and a starting of the system is prepared.