The invention discloses an electromagnetic eight-direction-independently-extendable/retractable wheel type mechanism for a snake-shaped robot. The mechanism comprises a shell, a connecting disk, a gravity sensing device, eight extending/retracting wheel holes, extending/retracting wheels, extending/retracting shafts, push-and-pull rods, electromagnet devices, permanent-magnetic slide blocks and a base. The eight extending/retracting wheel holes are uniformly distributed in the shell; and during the movement of the snake-shaped robot, the electromagnet devices are triggered to work through the control of the gravity sensing device, the permanent-magnetic slide blocks drive the push-and-pull rods to push out two extending/retracting wheels adjacent to a touchdown extending/retracting wheel hole under the action of corresponding magnetic force, the extending/retracting wheels retract when a touchdown direction changes, and corresponding extending/retracting wheels extend out again, so that the wheel extending/retracting function of the snake-shaped robot in wheel type movement is realized. The mechanism has the characteristics of simplicity in equipment and easiness in manufacturing, fast response and rapid wheel extending/retracting of the robot can be guaranteed during overturning, and then, the running speed of the robot is effectively increased.