A shock absorber that absorbs a vibration using a working fluid charged into a first chamber and a second chamber comprises a tube body, an inserted body, a tip end of which is inserted into the tube body from an end portion of the tube body, and a partition wall portion that is provided on the tip end of the inserted body to be capable of sliding within the tube body and partitions an interior of the tube body into the first chamber and the second chamber. The shock absorber comprises a connecting portion that is provided within a partition wall portion sliding region of the tube body and connects the first chamber and the second chamber when the partition wall portion passes thereby.