In one embodiment, a liquid treatment method includes (A) imaging a discharging port part of the liquid nozzle each time the discharging process is performed to one substrate, and acquiring, from images thus obtained, size data on foreign matter possibly present at the discharging port part; and (B) based on a history of the size data arranged in chronological order, judging whether an abnormality in substrate-processing has occurred. In the item (B), if the number of continuous acquisition, indicating how many times the size data not smaller than a first threshold value has been acquired continuously, exceeds a predetermined value, then judging that an abnormality in substrate-processing has occurred.