A fuel tank comprising: a housing having an inner space formed therein and including a nozzle part formed at a first side thereof to introduce fuel thereinto; an adsorber provided within the housing and configured to store fuel introduced through the nozzle part by adsorption; a diffuser located between the nozzle part and the adsorber within the housing and configured to diffuse the fuel introduced through the nozzle part and then to supply the fuel to the adsorber; and a filter unit configured to filter out foreign substances from the fuel diffused by the diffuser, wherein the housing includes a vessel part having both opened sides and an inner space formed therein such that the adsorber is provided within the inner space, a lid part combined with a first opened side of the vessel part and provided with the nozzle part, and a closure part combined with a second opened side of the vessel part to close the inner space, and wherein a partition extending in a length direction is provided within the housing to divide the inner space into sub-spaces, wherein the filter unit includes a first filter provided at a first side of the adsorber between the diffuser and the adsorber and a second filter provided at a second side of the adsorber, wherein an elastic support device is disposed between the vessel part and the closure part, wherein the first filter is located between the diffuser and the adsorber and contacts the first side of the adsorber, and the second filter is located at the second side of the adsorber, elastically supported in a sideward direction by the elastic support device provided at a second side of the housing, and closely adhered to the second side of the adsorber, and wherein the elastic support device includes a reinforcing plate including a plurality of through holes, and an elastic body provided at a first side of the reinforcing plate and pushing the reinforcing plate in a sideward direction. a housing having an inner space formed therein and including a nozzle part formed at a first side thereof to introduce fuel thereinto; an adsorber provided within the housing and configured to store fuel introduced through the nozzle part by adsorption; a diffuser located between the nozzle part and the adsorber within the housing and configured to diffuse the fuel introduced through the nozzle part and then to supply the fuel to the adsorber; and a filter unit configured to filter out foreign substances from the fuel diffused by the diffuser, wherein the housing includes a vessel part having both opened sides and an inner space formed therein such that the adsorber is provided within the inner space, a lid part combined with a first opened side of the vessel part and provided with the nozzle part, and a closure part combined with a second opened side of the vessel part to close the inner space, and wherein a partition extending in a length direction is provided within the housing to divide the inner space into sub-spaces, wherein the filter unit includes a first filter provided at a first side of the adsorber between the diffuser and the adsorber and a second filter provided at a second side of the adsorber, wherein an elastic support device is disposed between the vessel part and the closure part, wherein the first filter is located between the diffuser and the adsorber and contacts the first side of the adsorber, and the second filter is located at the second side of the adsorber, elastically supported in a sideward direction by the elastic support device provided at a second side of the housing, and closely adhered to the second side of the adsorber, and wherein the elastic support device includes a reinforcing plate including a plurality of through holes, and an elastic body provided at a first side of the reinforcing plate and pushing the reinforcing plate in a sideward direction.