. A lifting device for a treadmill having a substantially rectangular deck frame with a first cross bar on which a running belt transmission assembly is mounted while a front roller is driven in motion by means of a transmission belt, a running belt being rotatable by means of the front roller and a rear roller, a support wheel being fitted to both bottom inner sides at the rear end of the deck frame, an upright support being mounted at both sides of the front end of the deck frame, a console being disposed at the top of the upright support while a base seat is connected to the bottom thereof, the lifting device comprising:
a) a motor for positioning and transmitting a spindle pivotably connected to the bottom of the deck frame;
b) a socket screwed to the spindle and movable to and fro by rotating the spindle;
c) a T-shaped cross bar pivotably connected with the socket, the T-shaped cross bar extending between both sides of the deck frame; and
d) lifting rods each with one end connected to the T-shaped cross bar and with the other end pivotally connected to the front end of the base seat so as to form a pivot point;
whereby, when the lifting motor is actuated to allow the socket to be displaced by rotating the spindle and then the T-shaped cross bar and the lifting rods move in the desired direction, the inclination of the deck frame is adjustable and the deck frame is movable between the use position and the folded position.