Abstract: A seat apparatus used by a worker when effecting a job on an automobile is disclosed. The seat apparatus includes: a two-axis support device located above a horizontal feed path of an automobile body, for supporting a suspension carriage such that the carriage is movable in a substantially horizontal plane; a hanger arm attached to the suspension carriage; and a seat member provided on a lower end portion of the hanger arm which can enter the automobile body through its side opening, in a direction perpendicular to the feed path of the body. The seat member on which the worker sits is movable with the suspension carriage in the direction perpendicular to the feed path, and is thus selectively located in a retracted position outside the automobile body, or a working position inside the automobile body, at which the worker is able to effect the job.