It is an object of the present invention to prevent the connection part from excessively bending without changing the flexibility of a strain relief 10. The strain relief 10 has a plurality of enclosing parts 18 arranged in the axial direction and enclosing the axis, with a space part S formed between the adjacent enclosing parts 18 so that the strain relief 10 is freely bendable. The plurality of enclosing parts 18 are each provided at the distal end face thereof with a projection 34 projecting in the distal direction. The projection 34 comes into contact with the opposing enclosing part 18, whereby the degree of curvature when the strain relief 10 is curved is regulated.