<;P>;PROBLEM TO BE SOLVED: To provide an autonomous propulsion type capsule robot capable of being microminiaturized without a movable part at the outside. <;P>;SOLUTION: This capsule robot 1 is provided with a cylindrical main body 3, a movable body 4 stored in the main body 3 to be movable in parallel to an advancing direction of the main body 3, and a driving means 5 for moving the movable body 4 at high speed in an opposite direction of the advancing direction of the main body 3 in the main body 3 and for moving the movable body 4 at low speed in the advancing direction of the main body 3. The main body 3 is advanced based on momentum conservation law and static friction by moving of the movable body 4. <;P>;COPYRIGHT: (C)2007,JPO&INPIT