In an arm support apparatus, an weight attachment is provided for at least one specified link in links of a support member supporting a mount to be movable based on rotation of at least one of the links around a corresponding at least one of the joints. The at least one specified link is associated with at least one specified degree of freedom. The weight attachment is configured such that one or more weight members are attachable thereto. When the one or more weight members are attached to the weight attachment, the weight attachment is configured to substantially balance in weight with the mount on which the part of the arm is mounted while applying supporting force to the part of the arm mounted on the mount.