A colloidal damper includes: a cylinder; a piston guided and supported by the cylinder and defining a closed space in association with the cylinder; a porous body having a multiplicity of first pores and being housed in the closed space; a liquid contained in the closed space together with the porous body, the liquid flowing into the first pores of the porous body when pressurized, and flowing out from the first pores of the porous body when the pressure is relieved. The damper may include a partition wall which has a multiplicity of second pores and which isolates the porous body from a frictional area, each of the second pores having a diameter smaller than the outer diameter of the porous body. The porous body may have an outer diameter larger than the size of the gap formed between the cylinder and the piston.