permits a limited air flow is formed between the pistons and the connecting pipe further in the case where the internal volume of the connecting bar 41 is small small holes 86 86 may be formed in the connecting bar 41 as indicated by broken lines in fig1 to provide communication between the interior of the bar 41 and the exterior so as not to obstruct the flow of air to or from the cylinder 63 since the shock absorber of the present invention has two cylinders in a face to face relation i e acting in opposite directions with each other the impact force can be buffered under substantially the same conditions in both the case where the carrier member is to be moved and the case where it is to be stopped further since the air in one cylinder which has been compressed slowly flows out to the exterior through the piston cylinder gap the impact energy absorbed by the compressed air will not act as a repulsive force on the piston and therefore it is possible to buffer the impact force without pulsating the carrier member in the shock absorber according to this invention the piston cylinder arrangements allow rapid pressure build up therein so as to absorb the energy caused by impact of starting or stopping traveling and the gaps act as flow restrictions so as to.