An actuator capable of attaining high output. The actuator includes a frame structure part that forms a frame structure surrounding a housing part, and a volume change part housed in the housing part. The volume change part increases a volume thereof by input of external energy. The frame structure part has a higher Young's modulus than a Young's modulus of the volume change part. The housing part has an anisotropic shape, with a maximum width in first direction of the housing part longer than a maximum width in second direction different from the first direction of the housing part.