Abstract: In a cone type twin screw extruder, two rotor shafts are disposed in such a manner as to approach one another in the direction towards the leading edge, and to be rotatable. An interlocking device is provided on the side of the base portions of the rotor shafts for interlockingly connecting the rotor shafts with each other. The interlocking device has a pair of reduction gear devices disposed on the base portion sides of the rotor shafts, and the reduction gear is constituted of a spur gear train or a planetary gear train. High speed shafts of the reduction gears are interlockingly connected with bevel gear devices, and one shaft of the bevel gear device forms a connecting shaft projecting from the other bevel gear device side. Further, a pair of the connecting shafts are interlockingly connected with each other by a coupling device.