Two members and a colloidal damper disposed between two members (26; 30) which move relative to each other, for damping a relative movement of the two members (26; 30), comprising: a cylinder device including a housing connected to one of the two members (26; 30) and a piston connected to the other of the two members (26; 30) and configured to be slidable in the housing, the housing and the piston defining a chamber (62; 64), and a colloidal solution (90; 96) which is accommodated in the chamber (62; 64) and in which are mixed a first working fluid (88; 94) and porous bodies each having a multiplicity of pores; wherein the colloidal damper is configured to damp the relative movement of the two members (26; 30) by an inflow and an outflow of the first working fluid (88; 94) into and out of the pores of each of the porous bodies upon the relative movement of the two members (26; 30), wherein the colloidal solution (90; 96) is hermetically contained in a hermetically sealed container (80; 82) which has flexibility, the colloidal solution (90; 96) and the hermetically sealed container (80; 82) constitute a colloidal-solution sealed body (92; 98) which is configured such that a volume thereof decreases by the inflow of the first working fluid (88; 94) into the pores of each of the porous bodies where a pressure applied to the colloidal-solution sealed body (92; 98) increases and such that the volume thereof increases by the outflow of the first working fluid (88; 94) from the pores of each of the porous bodies where the pressure applied to the colloidal-solution sealed body (92; 98) decreases, and a second working fluid is contained in the chamber (62; 64) together with the colloidal-solution sealed body (92; 98), characterized in that, where the colloidal-solution sealed body (92; 98) is a first colloidal-solution sealed body, the colloidal damper comprises another colloidal-solution sealed body as a second colloidal-solution sealed body, the first colloidal-solution sealed body and the second colloidal-solution sealed body being accommodated in the chamber, and wherein, where the colloidal solution (90; 96) of the first colloidal-solution sealed body is a first colloidal solution, the second colloidal-solution sealed body includes a second colloidal solution different from the first colloidal solution in composition. a cylinder device including a housing connected to one of the two members (26; 30) and a piston connected to the other of the two members (26; 30) and configured to be slidable in the housing, the housing and the piston defining a chamber (62; 64), and a colloidal solution (90; 96) which is accommodated in the chamber (62; 64) and in which are mixed a first working fluid (88; 94) and porous bodies each having a multiplicity of pores; wherein the colloidal damper is configured to damp the relative movement of the two members (26; 30) by an inflow and an outflow of the first working fluid (88; 94) into and out of the pores of each of the porous bodies upon the relative movement of the two members (26; 30), wherein the colloidal solution (90; 96) is hermetically contained in a hermetically sealed container (80; 82) which has flexibility, the colloidal solution (90; 96) and the hermetically sealed container (80; 82) constitute a colloidal-solution sealed body (92; 98) which is configured such that a volume thereof decreases by the inflow of the first working fluid (88; 94) into the pores of each of the porous bodies where a pressure applied to the colloidal-solution sealed body (92; 98) increases and such that the volume thereof increases by the outflow of the first working fluid (88; 94) from the pores of each of the porous bodies where the pressure applied to the colloidal-solution sealed body (92; 98) decreases, and a second working fluid is contained in the chamber (62; 64) together with the colloidal-solution sealed body (92; 98), characterized in that, where the colloidal-solution sealed body (92; 98) is a first colloidal-solution sealed body, the colloidal damper comprises another colloidal-solution sealed body as a second colloidal-solution sealed body, the first colloidal-solution sealed body and the second colloidal-solution sealed body being accommodated in the chamber, and wherein, where the colloidal solution (90; 96) of the first colloidal-solution sealed body is a first colloidal solution, the second colloidal-solution sealed body includes a second colloidal solution different from the first colloidal solution in composition.