The present invention provides a method of estimating a state of health (SoH) of a lithium-sulfur battery, including the steps of: a) maintaining a state of health confirmation target battery in a rest state for 0.01 seconds or more in a state in which the state of health confirmation target battery is fully charged; b) measuring OCV (det) in a state in which a voltage drop is made during the rest state; c) calculating ΔOCV by subtracting OCV (det) from OCV (ini) previously measured in the same manner as in steps a) and b) at an initial stage of use of the state of health confirmation target battery; and d) estimating a state of health (%) of the battery from a magnitude of the ΔOCV.