A reactor module includes a pre-reactor and a membrane reactor disposed downstream of the pre-reactor. The membrane reactor includes a separation membrane. In the pre-reactor, an intermediate gas is generated from a source gas containing hydrogen and carbon oxide. The intermediate gas contains a liquid fuel, water vapor, and residual source gas. In the membrane reactor, the liquid fuel and water vapor are generated from the residual source gas. The separation membrane allows the water vapor contained in the intermediate gas and a product generated from the residual source gas to pass therethrough.