Abstract: A stirling cycle system driving device comprises a circumference cam having a circumferential guiding groove formed in the outer peripheral surface thereof, a piston rod and a displacer rod respectively having a wheel guided along said circumferential guiding groove, a crank case having guiding grooves for guiding said piston rod and said displacer rod only upward and downward, a piston and a displacer, and a cylinder case. According to the present invention, because a crank shaft is not needed, the device can be minified and the quantity of the working fluid can be decreased. Preferably, the device further comprises a following gear connected to the displacer rod and the piston rod, a driving gear engaged with said following gear, and a control motor for driving said driving gear, by which the phase angle between the piston and the displacer can be regulated.