A mobile robot has a seating part, a moving apparatus to move the seating part, and a robot part with a base part to be attached to the seating part, a body capable of rotating around a vertical axis normal to an attaching surface which the seating part to be attached to the base part, and an arm connected to the body having a plurality of joints. The seating part has a first surface facing a work that is subject to the operation by the robot part and a second surface that is different from the first surface, and the arms are formed such that the positional relationship between the arms and the first surface is substantially identical to the positional relationship between the arms and the second surface according to the rotation of the body around the vertical axis.