There is provided an operation control apparatus in a solar power system, which can widen an operation range of a power converter and can effectively use generated power of a solar battery. The solar power system supplies an alternating-current power system (4) with alternating-current power obtained by performing alternating-current power conversion on direct-current power from a solar battery (1) by a power converter (2), and includes a switch (5) between a link point between the power converter (2) and the alternating-current power system (4). The operation control apparatus includes a criterion calculator (15) that obtains an operation criterion of the power converter (2), based on a moving average voltage detected by the voltage detector (8), a direct-current voltage detector (10) that detects a direct-current output voltage of the solar battery (1), and an operation determination device (11) which is input with and compares both of a direct-current output voltage A detected by the direct-current voltage detector (10) and an operation criterion B obtained by the criterion calculator (15), compares, and supplies the power converter (2) with an operation command if the direct-current output voltage A is greater than the operation criterion B.