Provided are an electroencephalogram measurement system, electroencephalogram measurement method, program, and non-transitory storage medium, all of which are configured or designed to reduce the chances of artifacts causing a decline in the accuracy of the electroencephalogram measured. An electroencephalogram measurement system (10) includes an acquisition unit (211), a decision unit (214), and an output unit (217). The acquisition unit (211) acquires electroencephalogram information representing an electroencephalogram obtained by an electrode unit (11) placed on a region of interest that forms part of a subject's (5) head (52). The decision unit (214) makes a decision, based on the electroencephalogram information acquired by the acquisition unit (211), whether or not there are any artifacts. The output unit (217) outputs the decision made by the decision unit (214).