There is provided a novel process for producing an indole derivative which comprises cyclizing 2-nitrobenzylcarbony compound in the presence of a catalyst comprising a Group VIII metal of the Periodic Table, characterized by conducting the cyclization in a gas atmosphere containing carbon monoxide. The process enables an indole compound to be selectively produced in a high yield from 2-nitrobenzylcarbonyl compound, and hardly yields an indoline compound as a reduction by-product that has been a problem in the catalytic hydrogenation method employing a noble metal catalyst. The indole derivative produced by the present process is useful for various fine chemical intermediates including compounds and physiologically active substances such as pharmaceuticals and agrochemicals.