The purpose of the present invention is to provide an assistance robot capable of supporting the sitting action of a person receiving assistance, in accordance with a variety of usage states. Action processing performed on the basis of a sitting trajectory for the assistance robot includes: a retraction step in which a holding member is lowered or raised to a fixed sitting position and the holding member is retracted, said fixed sitting position being a position at which the buttocks of the person receiving assistance are positioned above the seat surface and at a prescribed height from the floor surface； and a lowering step in which the holding member is lowered from the fixed sitting position until the person receiving assistance is seated on the seat surface.
