A substrate solution-processing method comprising the steps of preparing a pair of spin chucks by which semiconductor wafers are supported, a housing by which the wafers supported by the spin chucks are enclosed, motor for rotating the spin chucks, a nozzle through which developing or resist solution is applied to each wafer, means for moving the nozzle between the wafers, and a waiting trench at which the nozzle is kept waiting, setting substantially same the times needed to finish the cycles of processing the wafers supported on at least two spin chucks and delaying one process cycle from the other, and keeping the nozzle waiting at the waiting trench unless developing or resist solution is applied to each wafer through the nozzle.