An attack scenario generation device 10 has: a first attack step detection unit 11 that executes an attack simulation on a first virtual model acquired from a storage device in which a plurality of virtual models used for representing a target system are stored and that detects a first attack step that satisfies a damage condition at which damage is inflicted on the first virtual model; an input/output condition extraction unit 12 that extracts, from the detected first attack step, an input condition or an output condition of the first virtual model, or both thereof; a second attack step detection unit 13 that executes an attack simulation on a second virtual model acquired from the storage device and that detects a second attack step that causes the output of the second virtual model to satisfy the input condition; and a combination unit 14 that generates an attack scenario by combining the first attack step and the second attack step.