A laundry treating apparatus comprising: a cabinet having a front face with a drawer hole defined therein, and a rear cover for forming a rear face of the cabinet; a drawer including a drawer body extendable from the cabinet through the drawer hole, a drawer cover for forming a top face of the drawer body, and a cover through-hole defined to penetrate the drawer cover, wherein the cover through-hole is exposed to the outside of the cabinet when the drawer body is extended from the cabinet; a tub including a tub body disposed inside the drawer and storing water therein, a tub cover for forming a top face of the tub body, and an inlet defined to penetrate the tub cover, wherein the inlet is exposed to the outside of the drawer through the cover through-hole; a drum rotatably disposed in the tub, wherein the drum accommodates laundry; a gasket fixed to the tub cover and surrounding an edge of the inlet; and a door for closing the inlet by pressing the gasket; a first guide and a second guide for providing a path for the door to reciprocate between a first point where the inlet is closed and a second point where the inlet is opened in a space defined between the tub cover and the drawer cover, wherein the first guide and the second guide are respectively disposed on portions to the left and to the right of the inlet; characterized in that the laundry treatment apparatus further comprises: a third guide for providing the path for the door to reciprocate between the first point and the second point, wherein the third guide extends from a rear end of the inlet toward a rear end of the tub cover, wherein the third guide is positioned between the first guide and the second guide; and a door lock for detachably fixing the door to a point positioned in front of the inlet in a space provided by the tub cover when the door is located at the first point. a cabinet having a front face with a drawer hole defined therein, and a rear cover for forming a rear face of the cabinet; a drawer including a drawer body extendable from the cabinet through the drawer hole, a drawer cover for forming a top face of the drawer body, and a cover through-hole defined to penetrate the drawer cover, wherein the cover through-hole is exposed to the outside of the cabinet when the drawer body is extended from the cabinet; a tub including a tub body disposed inside the drawer and storing water therein, a tub cover for forming a top face of the tub body, and an inlet defined to penetrate the tub cover, wherein the inlet is exposed to the outside of the drawer through the cover through-hole; a drum rotatably disposed in the tub, wherein the drum accommodates laundry; a gasket fixed to the tub cover and surrounding an edge of the inlet; and a door for closing the inlet by pressing the gasket; a first guide and a second guide for providing a path for the door to reciprocate between a first point where the inlet is closed and a second point where the inlet is opened in a space defined between the tub cover and the drawer cover, wherein the first guide and the second guide are respectively disposed on portions to the left and to the right of the inlet; a third guide for providing the path for the door to reciprocate between the first point and the second point, wherein the third guide extends from a rear end of the inlet toward a rear end of the tub cover, wherein the third guide is positioned between the first guide and the second guide; and a door lock for detachably fixing the door to a point positioned in front of the inlet in a space provided by the tub cover when the door is located at the first point.