The invention provides a three-degree-of-freedom surface-movable robot finger unit device, and belongs to the technical field of robot hands. The three-degree-of-freedom surface-movable robot finger unit device comprises two finger sections, four bevel gears, a left half shaft, a right half shaft, a left joint driver, a right joint driver, a left joint transmission mechanism, a right joint transmission mechanism, a longitudinal shaft, a longitudinal moving driver, a longitudinal moving transmission mechanism, a skin layer and the like. A joint double-degree-of-freedom orthogonal rotation function is fulfilled, namely the device can be bent around a joint shaft and rotate around the longitudinal shaft, and a surface longitudinal moving function is also fulfilled. The device is suitable to be mounted on a finger of a robot, functions of fingers of a humanoid robot are expanded, and in a movement process, adjacent fingers cannot intervene. The device is provided with a finger surface capable of moving multi-dimensionally, by surface movement, an object can relatively move or deform, the device is suitable for picking up objects, and is particularly suitable for picking up flat objects and deformable objects, and positions and postures of a grabbed object can be adjusted. The device is compact in structure, small in size, easy to control and suitable for being mounted on a hand of the robot.