An apparatus for intermittently manufacturing a raw rubber strip comprises a screw extruder, an extruder head having a preforming nozzle, a gear pump therebetween, a pair of calendar rolls, a roll-gap changer for switching between a close state and an open state of calendar rolls, and a controller for controlling the gear pump, the calendar rolls and the roll-gap changer to let the calendar rolls in the open state prior to the stopping of the rotation of the calendar rolls.