Reactor

A monolith-type reactor used for a conversion reaction for converting a raw material gas into a liquid fuel, the raw material gas containing at least hydrogen and carbon oxide, the reactor comprising:

• a porous support body;
• a plurality of first cells passing through the porous support body in a first direction, the raw material gas flowing through the plurality of first cells;
• a plurality of second cells extending inside the porous support body in the first direction, a sweep gas flowing through the plurality of second cells;
• a separation membrane formed on an inner peripheral surface of each of the plurality of first cells, and permeable to a product of the conversion reaction;
• and
• a catalyst disposed inside the separation membrane and configured to promote the conversion reaction, wherein
• in a cross section taken along a second direction perpendicular to the first direction, an average cross-sectional area of the plurality of first cells is larger than an average cross-sectional area of the plurality of second cells.