Provided is a sight line movement detection method, in which a computer executes steps comprising: an acquisition step of acquiring ocular potential-associated signals which relate to ocular potentials which are detected by each electrode which makes contact with the periphery of a subject's eye； a first detection step of detecting a sight line movement on the basis of whether the ocular potential-associated signals exceed a first threshold； an assessment step of assessing whether the elapsed time from a first time at which the sight line movement is detected is within a prescribed time； a determination step of determining, on the basis of the result of the elapsed time assessment, whether to use as the threshold the first threshold or a second threshold which has a larger absolute value than the first threshold； and a second detection step of detecting the sight line movement on the basis of whether the ocular potential-associated signals after the first time have exceeded the determined threshold.
