According to the Seismological Center of the Geophysics Institute of Tehran University, the quake occurred at 0:08 hours local time (8:38 GMT) at the depth of 8 km underground.
The epicenter of the quake was 78km from Kermanshah.
No report has so far been released on the likely casualties or damage to property.
Iran sits on major fault lines and is prone to near-daily earthquakes.
On November 12, 2017, a fatal 7.3-measuring earthquake hit the provincial city of Salas Babajani killing 620 people and injuring about 12,000 others.