The present invention provides a robot apparatus is capable of moving autonomously, flexibly responding to a motion of conforming to an external moving subject that may typically be the user of the robot apparatus and conforming to the motion of the moving subject, and also capable of modifying the conforming relationship with the moving subject. The robot apparatus is capable of moving autonomously, and comprises an input section that inputs an image or sound of an external moving subject, a plurality of motion generating sections that generate a plurality different motions in response to the image or sound input by way of the input section, conforming to the motion of the external moving subject, a motion expressing section that integrally expresses one or more than one motions out of the plurality of motions generated by the plurality of motion generating sections, and a control section that controls the number of motions integrated by the motion expressing section and the ratio of the motions to be integrated.