A riding device includes a bottom base and an intermediate base pivotally positioned on the bottom base and having its front and rear end respectively and pivotally provided with two front and two rear swing arms. A seat plate positioned over the intermediate base has four corners with a connecting lug connected with the upper ends of the swing arms. A transmission unit fixed on the intermediate base has a motor for driving a first, a second and a third gear to rotate synchronously. A crank is secured on the shaft of the second gear. A pull rod is connected with the bottom base and also with the shaft of the third gear. The riding device of this invention can swing back and forth, swing up and down and swing left and right obliquely.