A fracture determination method for determining a fracture of a metal structure includes, when a fracture determination target portion has returned from a plastic state to an elastic state, given that a stress when the portion returned to the elastic state is (x, y)=(σ2, σ1) (maximum principal stress: σ1, minimum principal stress: σ2) on a (x, y) coordinate plane, performing fracture determination of the fracture determination target portion using a re-yield stress R determined by the intersection between a straight line satisfying a relation y=(σ1/σ2)x and an yield curve obtained from the plastic state of the fracture determination target portion. Fracture determination can be performed with high accuracy even when the fracture determination target portion has returned from a plastic state to an elastic state.