An aid device that assists the operation of transferring a person being assisted and comprises: a base upon which feet of the person being assisted are placed； a support arm section that is capable of supporting part of the body of the person being assisted, is provided on the base, and is capable of operations having as the operation directions thereof a standing direction in which the person being assisted is caused to stand and a seating direction in which the person being assisted is caused to sit； an actuator that drives the support arm section； a link mechanism that transmits the drive force of the actuator to the support arm section and permits change in the current position of the support arm section driven by the actuator, without relying on the drive state of the actuator； and a damper mechanism that generates a resistance force against at least one side in the operation directions of the support arm section.
