A life determination device comprises: an image acquiring unit that acquires an image showing a result of machining by cutting on a target of the machining by cutting; a feature quantity acquiring unit that acquires a feature quantity indicating the quality of the result of the machining by cutting from the image acquired by the image acquiring unit; and a life determining unit that determines the life of a cutting tool having been used for the machining by cutting on the target based on the feature quantity acquired by the feature quantity acquiring unit.