The method for determining a depression state of the present invention comprises the steps of: measuring a pulsation interval of a subject, and an acceleration or an angular velocity associated with a movement of the subject (that is hereinafter referred to as an "activity")； and determining the subject to be a depression state when at least one of the following conditions [A] and [B] is satisfied: [A] In an awaking time zone of the subject, at least one of the following formulas is calculated and satisfied: the pulsation interval × the activity <； C1, HF × the activity <； C2, (LF/HF) / the activity >； C3； [B] In a sleeping time zone of the subject, at least one of the following formulas is calculated and satisfied: the pulsation interval / the activity <； C4, HF / the activity <； C5, (LF/HF) × the activity >； C6.
