A driving and resistance device for stationary bikes includes a frame including two boards between which a flywheel is located, a shaft extends through the flywheel and the two boards. A driving wheel is mounted to the shaft and drives the flywheel. The driving unit includes a first belt, a second belt, an idle wheel unit, an intermediate wheel unit and a passive wheel, the passive wheel is connected to a sleeve which is secured to the shaft. The driving wheel is driven by rotating the cranks on two ends of the shaft and the first belt, the intermediate wheel unit, the second belt, the passive wheel, the sleeve and the flywheel are driven in sequence. Because the driving wheel and the flywheel share the same shaft so that the driving and resistance device is compact.