CURRENT COLLECTION BOX

A current collection box (4) is provided with lines (La to Ld) which are connected to each of a plurality of solar cells (1a to 1d), and boosting circuits (41a to 41 d) which are interposed upon each of at least two or more lines of the plurality of lines (La to Ld) so as to boost the output voltage of the solar cells (1a to 1d), and outputs the output of each of the lines (La to Ld) together. In the current collection box (4), each of the boosting circuits (41a to 41d) starts MPPT operation, which operates so that the output power of the solar cells (1a to 1d) is maximized, with different periods each.