The invention discloses a direct current steam generator, which comprises a container main body, a tube plate, a heat exchange tube, a water supply pipe and a chamber separator; a central channel, a first chamber and a second chamber are arranged inside the container main body; the water supply pipe is arranged in the central channel, and the heat exchange pipe is arranged in the first chamber; a chamber separator is disposed in the second chamber, dividing the second chamber into upper and lower chambers separated from each other; a water header and a steam header are disposed on the tube plate; a nozzle is arranged on a side surface of the contain main body; a water inlet channel of the nozzle is connected with the upper chamber, the first chamber, the lower chamber and a water outlet channel of the nozzle in sequence to form a primary-side medium channel; and the water supply header, the water supply pipeline, an internal channel of the heat exchange tube and the steam header communicate with each other successively to form a secondary side medium channel. The DC steam generator facilitates compact arrangement. In addition, the use of a spiral coil as the heat exchange tube enhances heat transfer and effectively solves the problem of thermal stress of the heat exchange tube.