Abstract: An assembly and disassembly-type damping force adjustable shock absorber is provided comprising a cylinder casing, an upper cap and a lower cap, a bottom valve body mounted on the lower cap, a rod inserted into the upper cap, and a piston valve body disposed on an end of the rod, wherein the piston valve body faces the bottom valve body, wherein the piston valve body determines a flow direction of the working fluid between the upper chamber and the lower chamber when the rod is expanded and contracted.