An omni-directional drive device, comprising: a base; a first power transmitting member and a second power transmitting member rotatably supported by the base in a mutually coaxial relationship; a first drive unit and a second drive unit for rotatively actuating the first and second power transmitting members, respectively; a plurality of first free rollers rotatably supported by the first power transmitting member and arranged along a first circle concentric with a rotational axis of the first power transmitting member, each first free roller having a rotation axis which is related to the rotational axis of the first power transmitting member as skew lines; a plurality of second free rollers rotatably supported by the second power transmitting member and arranged along a second circle concentric with the rotational axis of the second power transmitting member, each second free roller having a rotation axis which is related to the rotational axis of the second power transmitting member as skew lines; and a main wheel including an annular member configured to rotate around a cross sectional center line thereof, and engaged by the first and second free rollers in such a manner that a lateral force of each free roller is transmitted to the main wheel so as to cause a circumferential movement of the main wheel along a circumference thereof and a rotational movement of the annular member around the cross sectional center line thereof characterized in that the main wheel comprises an annular shaft and a plurality of discrete sleeves fitted on the annular shaft, each in a freely rotatable manner, such that the sleeves are engaged by the first and second free rollers. a base; a first power transmitting member and a second power transmitting member rotatably supported by the base in a mutually coaxial relationship; a first drive unit and a second drive unit for rotatively actuating the first and second power transmitting members, respectively; a plurality of first free rollers rotatably supported by the first power transmitting member and arranged along a first circle concentric with a rotational axis of the first power transmitting member, each first free roller having a rotation axis which is related to the rotational axis of the first power transmitting member as skew lines; a plurality of second free rollers rotatably supported by the second power transmitting member and arranged along a second circle concentric with the rotational axis of the second power transmitting member, each second free roller having a rotation axis which is related to the rotational axis of the second power transmitting member as skew lines; and a main wheel including an annular member configured to rotate around a cross sectional center line thereof, and engaged by the first and second free rollers in such a manner that a lateral force of each free roller is transmitted to the main wheel so as to cause a circumferential movement of the main wheel along a circumference thereof and a rotational movement of the annular member around the cross sectional center line thereof characterized in that the main wheel comprises an annular shaft and a plurality of discrete sleeves fitted on the annular shaft, each in a freely rotatable manner, such that the sleeves are engaged by the first and second free rollers.