A vacuum cleaner comprising: a cleaner body including a motor configured to generate a suction force and a foreign substance collection chamber; and a suction head connected to the cleaner body and including: a housing (111, 112L, 112R, 113) having a suction port, a drum brush, and a one-way roller disposed in front of the drum brush, wherein the drum brush and the one-way roller are configured so that, when the suction head is moving forward on a surface to be cleaned, the drum brush and the one-way roller rotate so that foreign substances on the surface are suctioned by the suction force into the housing through the suction port to be guided to the foreign substance collection chamber, and when the suction head is moving rearward on the surface, rotation of the one-way roller is restricted to prevent the foreign substances suctioned into the housing from being discharged outside of the housing of the suction head through the suction port, wherein the one-way roller includes: a roller shaft, and a roller body that is fixed to an outer circumferential surface of the roller shaft and configured so that, when the suction head is on the surface, the roller body contacts at least some of the foreign substances on the surface under the suction head, wherein the vacuum cleaner further includes a one-way clutch bearing connected to at least one end of the roller shaft and configured to support the at least one end of the roller shaft. a cleaner body including a motor configured to generate a suction force and a foreign substance collection chamber; and a suction head connected to the cleaner body and including: a housing (111, 112L, 112R, 113) having a suction port, a drum brush, and a one-way roller disposed in front of the drum brush, wherein the drum brush and the one-way roller are configured so that, when the suction head is moving forward on a surface to be cleaned, the drum brush and the one-way roller rotate so that foreign substances on the surface are suctioned by the suction force into the housing through the suction port to be guided to the foreign substance collection chamber, and when the suction head is moving rearward on the surface, rotation of the one-way roller is restricted to prevent the foreign substances suctioned into the housing from being discharged outside of the housing of the suction head through the suction port, wherein the one-way roller includes: a roller shaft, and a roller body that is fixed to an outer circumferential surface of the roller shaft and configured so that, when the suction head is on the surface, the roller body contacts at least some of the foreign substances on the surface under the suction head, wherein the vacuum cleaner further includes a one-way clutch bearing connected to at least one end of the roller shaft and configured to support the at least one end of the roller shaft. a housing (111, 112L, 112R, 113) having a suction port, a drum brush, and a one-way roller disposed in front of the drum brush, wherein the drum brush and the one-way roller are configured so that, when the suction head is moving forward on a surface to be cleaned, the drum brush and the one-way roller rotate so that foreign substances on the surface are suctioned by the suction force into the housing through the suction port to be guided to the foreign substance collection chamber, and when the suction head is moving rearward on the surface, rotation of the one-way roller is restricted to prevent the foreign substances suctioned into the housing from being discharged outside of the housing of the suction head through the suction port, wherein the one-way roller includes: a roller shaft, and a roller body that is fixed to an outer circumferential surface of the roller shaft and configured so that, when the suction head is on the surface, the roller body contacts at least some of the foreign substances on the surface under the suction head, wherein the vacuum cleaner further includes a one-way clutch bearing connected to at least one end of the roller shaft and configured to support the at least one end of the roller shaft. a roller shaft, and a roller body that is fixed to an outer circumferential surface of the roller shaft and configured so that, when the suction head is on the surface, the roller body contacts at least some of the foreign substances on the surface under the suction head, wherein the vacuum cleaner further includes a one-way clutch bearing connected to at least one end of the roller shaft and configured to support the at least one end of the roller shaft.