Provided are a method for producing an organic substance and an apparatus for producing an organic substance that are capable of efficiently cooling a synthesis gas and converting the synthesis gas to an organic substance at a high conversion efficiency using a microbial catalyst. A method for producing an organic substance includes a step of passing a synthesis gas G1 discharged from a gasifier 2 through a heat exchanger 20 to cool the synthesis gas G1, a step of passing the synthesis gas G1 cooled with the heat exchanger 20 through a gas cooling tower 21 to cool the synthesis gas G1 with water sprayed in the gas cooling tower 21 and a step of bringing the synthesis gas G1 that has passed through at least the heat exchanger 20 and the gas cooling tower 21 into contact with a microbial catalyst to generate an organic substance.

Provided are a method for producing an organic substance and an apparatus for producing an organic substance that are capable of efficiently cooling a synthesis gas and converting the synthesis gas to an organic substance at a high conversion efficiency using a microbial catalyst. A method for producing an organic substance includes a step of passing a synthesis gas G1 discharged from a gasifier 2 through a heat exchanger 20 to cool the synthesis gas G1, a step of passing the synthesis gas G1 cooled with the heat exchanger 20 through a gas cooling tower 21 to cool the synthesis gas G1 with water sprayed in the gas cooling tower 21 and a step of bringing the synthesis gas G1 that has passed through at least the heat exchanger 20 and the gas cooling tower 21 into contact with a microbial catalyst to generate an organic substance.