A tilting and folding device of a treadmill includes a base and a track bed is pivotably connected to the base by an arm, a support device and an actuator. The arm is pivotably connected between the base and the track bed. The actuator is pivotably connected between the base and a pivotal portion located between the first and second pivotal ends. The support device is pivotably connected to the base and the track bed. When the arm is pivoted about the second pivotal end and driven by the actuator, the front end of the track bed is lifted and stopped after being traveled to a pre-set stroke. When the actuator continuously drives the arm, the rear end of the track bed is supported by the support device and pivoted until the track bed is located upright.