An elapsed-time determination apparatus includes: a storage unit that stores correlation information indicating a correlation between a state of a melanophore of a fish and an amount of time elapsed since the death of the fish; an acquisition unit that acquires an image of a fish; an analysis unit that detects a state of a melanophore of a fish by analyzing an image acquired by the acquisition unit; and a determination unit that determines the amount of time elapsed since the death of the fish in accordance with the state of the melanophore of the fish detected by the analysis unit, based on the correlation information, and outputs determination results.