To provide a crane device for a marine vessel capable of eliminating marine contamination caused by oil, reducing the number of parts by not requiring an inverter for converting DC power to AC power, simplifying the structure, easily performing manufacture and assembling work, reducing the facility cost, and operating a turning base by accumulated power during an emergency of a marine vessel.

A mounting ring 12 is connected to a crane installing base 11, and an annular rack 13 is connected to the mounting ring 12 by a bolt 14. A turning ring 15 is turnably attached to the annular rack 13 via a bearing 16, and the turning base 17 is connected to the turning ring 15 by a bolt 18. A housing 21 is connected to the turning base 17, and a DC electric motor 23 is mounted at an upper part of the housing 21. A pinion 28 is connected to a rotary shaft 25 of the DC electric motor 23 via a gear speed reduction mechanism 26 and an output shaft 27, and the pinion 28 is meshed with a tooth part 13a of the annular rack 13.