A clothes treatment device comprising: a housing tub for housing clothing; and a steam supply mechanism for supplying steam to the housing tub, wherein the steam supply mechanism includes: a steam generator having a wall surface which defines a chamber for generating the steam; a heater for heating the wall surface; a water supply mechanism for injecting water to the wall surface; a nozzle mounted on the housing tub; an impurity removing part having open holes formed on the nozzle and being formed of a plate-like member where a large number of circular holes are formed in the plate-like member or a grid-shaped plate-like member; and a guide pipe which guides the steam to the nozzle from the steam generator, and the steam injected from the nozzle is supplied to an inside of the housing tub through the impurity removing part, characterized in that the guide pipe comprises: a steam communication tube connected to the steam generator at one end; a branched tube connected to the other end of the steam communication tube; and a steam tube connecting the branched tube and the nozzle, wherein the branched tube includes: a main tube connected to the steam communication tube; an upper sub tube bent upward from the main tube; and a lower sub tube bent downward from the main tube, wherein water which flows into the branched tube flows downward through the lower sub tube; wherein the steam tube is connected to the upper sub tube, and wherein an angle included by the main tube and the upper sub tube is an obtuse angle, and an angle included by the main tube and the lower sub tube is an acute angle. a housing tub for housing clothing; and a steam supply mechanism for supplying steam to the housing tub, wherein the steam supply mechanism includes: a steam generator having a wall surface which defines a chamber for generating the steam; a heater for heating the wall surface; a water supply mechanism for injecting water to the wall surface; a nozzle mounted on the housing tub; an impurity removing part having open holes formed on the nozzle and being formed of a plate-like member where a large number of circular holes are formed in the plate-like member or a grid-shaped plate-like member; and a guide pipe which guides the steam to the nozzle from the steam generator, and the steam injected from the nozzle is supplied to an inside of the housing tub through the impurity removing part, characterized in that the guide pipe comprises: a steam communication tube connected to the steam generator at one end; a branched tube connected to the other end of the steam communication tube; and a steam tube connecting the branched tube and the nozzle, a steam communication tube connected to the steam generator at one end; a branched tube connected to the other end of the steam communication tube; and a steam tube connecting the branched tube and the nozzle, wherein the branched tube includes: a main tube connected to the steam communication tube; an upper sub tube bent upward from the main tube; and a lower sub tube bent downward from the main tube, wherein water which flows into the branched tube flows downward through the lower sub tube; wherein the steam tube is connected to the upper sub tube, and wherein an angle included by the main tube and the upper sub tube is an obtuse angle, and an angle included by the main tube and the lower sub tube is an acute angle. a main tube connected to the steam communication tube; an upper sub tube bent upward from the main tube; and a lower sub tube bent downward from the main tube, wherein water which flows into the branched tube flows downward through the lower sub tube; wherein the steam tube is connected to the upper sub tube, and wherein an angle included by the main tube and the upper sub tube is an obtuse angle, and an angle included by the main tube and the lower sub tube is an acute angle.