A self-propelled carriage 10a in which a spherical drive module 10 is mounted on the bottom of a carriage frame 11 via a suspension mechanism 12. The spherical drive module 10 includes a spherical body 14 and first and second contacts with the spherical body 14 from the XY axis direction. Driving wheels 15 and 16, and first and second free balls that are opposite to the first and second driving wheels 15 and 16 and receive reaction force from the first and second driving wheels 15 and 16. A bearing mechanism 17, 18, a third universal ball bearing mechanism 19 that is located above the sphere 14 and receives a load applied to the sphere 14, and a base 20 that supports them.球体駆動モジュール１０を台車フレーム１１の底にサスペンション機構１２を介して装着した自走台車１０ａであって、球体駆動モジュール１０は、球体１４と、球体１４にＸＹ軸方向から接する第１、第２の駆動車輪１５、１６と、第１、第２の駆動車輪１５、１６と反対側にあって第１、第２の駆動車輪１５、１６からの反力を受ける第１、第２の自在球軸受機構１７、１８と、球体１４の上位置にあって、球体１４に掛かる荷重を受ける第３の自在球軸受機構１９と、これらを支持する基台２０とを備える。
