A substrate transfer system includes a substrate transfer robot disposed in a robot installment area defined between a first apparatus and a second apparatus. The first apparatus includes cassettes. The cassettes are each configured to accommodate at least one substrate. The second apparatus includes a second wall opposite to a first wall. The substrate transfer robot transfers the at least one substrate from each of the cassettes to the second apparatus. The substrate transfer robot includes a base stationary, a hand, and arms. A first arm includes a first end and a second end. The first end is rotatably coupled to the base. A second arm includes a third end and a fourth end. The third end is rotatably coupled to the second end. The second end of the first arm moves beyond the second wall when the substrate transfer robot takes out the substrate from the first apparatus.