A self propelling device is attached to a front end side of an insert section of an endoscope and propels the front end side in a body. The self propelling device has an internal cylinder into which the front end side is inserted and an external cylinder surrounding the internal cylinder. A rotating body is rotatably attached to the external cylinder in an axis direction along the inner periphery and the outer periphery of the external cylinder, and the self propelling device propels by rotation of the rotating body. The inner diameter of the internal cylinder is large, and the front end side can be bendable in the internal cylinder. A coil spring formed in a circular truncated cone shape is located in the internal cylinder. The coil spring has a bottom having large diameter which is fixed to the internal cylinder and has a top having small diameter which is fit on the front end side of the insert section. The self propelling device and the front end side of the insert section are connected via the coil spring so that they can relatively move.
