A robot apparatus includes: a base plate; a rotation-driving motor provided on the base plate; a transmission mechanism that is provided on a bottom surface side of the base plate and to which a rotational force of the rotation-driving motor is transmitted; and a rotation-driving mechanism that is provided on the bottom surface side of the base plate and to which the rotational force of the rotation-driving motor is input via the transmission mechanism. A workpiece is rotated by the rotation-driving mechanism at an end of the rotation-driving mechanism opposite to the base plate.