A laundry treatment apparatus comprising: a housing; a tub comprising a tub body and a tub cover and provided in the housing to store water; a heater configured to heat the water stored in the tub; a drum rotatably disposed inside the tub to accommodate laundry; a driving unit located at an outside of the bottom surface of the tub to rotate the drum; and an accommodation unit provided at a rear side of a bottom surface of the tub, and recessed downward from the bottom surface of the tub to define a space for accommodating the heater, wherein the tub body comprises the bottom surface and a side surface being perpendicular to the bottom surface and has a curved front side surface and two flat rear side surfaces (S1, S2), and the first flat rear side surface is defined between a first point and a contact point, and the second flat rear side surface is defined between the contact point and a second point, wherein the first point is located at the rear side of the bottom surface of the tub from a center, and the contact point is located at a first tangent and a second tangent, where the tangents intersect each other, and the first tangent is a tangent of the first point, and the second tangent is a tangent of the second point located at the outer circumference of the bottom surface of the tub, which is rotated by a predetermined angle (θ) from the first point located at the outer circumference of the bottom surface of the tub on the basis of the center of the bottom surface of the tub, wherein the accommodation unit is quadrangular, a portion of the rear side of the bottom surface of the tub provided with the accommodation unit extends parallel to a rear surface of the housing, and a side surface of the accommodation unit is parallel to the first flat rear side surface of the two flat rear side surfaces of the tub, wherein the second flat rear side surface of the two flat rear side surfaces of the tub is extended from one side of the first flat rear side surface and forms a predetermined angle with the first rear side surface. a housing; a tub comprising a tub body and a tub cover and provided in the housing to store water; a heater configured to heat the water stored in the tub; a drum rotatably disposed inside the tub to accommodate laundry; a driving unit located at an outside of the bottom surface of the tub to rotate the drum; and an accommodation unit provided at a rear side of a bottom surface of the tub, and recessed downward from the bottom surface of the tub to define a space for accommodating the heater, wherein the tub body comprises the bottom surface and a side surface being perpendicular to the bottom surface and has a curved front side surface and two flat rear side surfaces (S1, S2), and the first flat rear side surface is defined between a first point and a contact point, and the second flat rear side surface is defined between the contact point and a second point, wherein the first point is located at the rear side of the bottom surface of the tub from a center, and the contact point is located at a first tangent and a second tangent, where the tangents intersect each other, and the first tangent is a tangent of the first point, and the second tangent is a tangent of the second point located at the outer circumference of the bottom surface of the tub, which is rotated by a predetermined angle (θ) from the first point located at the outer circumference of the bottom surface of the tub on the basis of the center of the bottom surface of the tub, wherein the accommodation unit is quadrangular, a portion of the rear side of the bottom surface of the tub provided with the accommodation unit extends parallel to a rear surface of the housing, and a side surface of the accommodation unit is parallel to the first flat rear side surface of the two flat rear side surfaces of the tub, wherein the second flat rear side surface of the two flat rear side surfaces of the tub is extended from one side of the first flat rear side surface and forms a predetermined angle with the first rear side surface.