For the multi-source method suitable to measure the photoelectric
conversion characteristics of a stacked solar cell, the light-receiving
area of the solar cell to be measured is limited to the minimal area of
laboratory level, and it is hard to measure a cell, module, or array
having an area more than 400 cm.sup.2. To cope with this problem, the
irradiance of irradiation light is measured or adjusted, the current vs.
voltage characteristic of a reference cell is measured, and the current
vs. voltage characteristic of a sample cell is measured. Next, the current
vs. voltage characteristic of the reference cell in standard test
conditions is compared with the measurement result of the current vs.
voltage characteristic of the reference cell, thereby obtaining a shift of
the measurement result from the standard test condition on the basis of
the shift of the irradiation light from the standard test condition. On
the basis of the obtained shift of the measurement result, the measurement
result of the current vs. voltage characteristic of the sample cell is
corrected, and the photoelectric conversion characteristics of the sample
cell are obtained.