The invention belongs to the field of deep sea rock core sampling, and belongs to a small-size rock core sampling drilling machine based on manned deep submersible vehicle mechanical hand operation. The small-size rock core sampling drilling machine comprises a battery, a control cabin, a water-tight cable, a handle, a drill tool, a deep water transmission unit, a transmission soft shaft and a deep water power unit, wherein the battery and the control cabin are connected through the water-tight cable and the deep water power unit, the deep water power unit is connected with the transmission unit through the soft shaft, the transmission unit and the drill tool are connected through screw threads, and the whole drilling machine is arranged in a sampling basket arranged at the front end of a manned deep submersible vehicle. The small-size rock core sampling drilling machine is a special seabed crusting rock core drilling machine designed and manufactured for the manned deep submersible vehicle, the design and the manufacturing are in accordance with the principles of safety, reliability, advancing, economy and practicability, the small-size rock core sampling drilling machine can be arranged on a sampling basket support frame of the manned deep submersible vehicle, and the effective drilling core taking can be realized on the seabed crusting through adopting a mechanical hand operation mode. The small-size rock core sampling drilling machine is mainly used for sampling the seabed crusting rock cores, and has higher practicability.