To provide a brassiere with a belt solving the following problems: a conventional brassiere having tapes tied at the front of the brassiere too much tightens the wearer's body ranging from the chest part to the stomach part to be suitable for a middle or old age person because of requiring a certain level of chest muscular force to take breath; and the conventional brassiere is inconvenient because a crossing part at the back center part is not stable and the tape at the waist crawls up when loosened in order to readily wear the brassiere.

The brassiere with a belt is structured as follows: extending both side surfaces of the brassiere obliquely downward instead of the back center part in conventional one to form the back center part into a Y-shape; forming an angle at the center part; attaching L-shaped hooks at the Y-shaped both side center parts so as to make the brassiere freely openable and adjustable in the size; attaching a belt loop at a Y-shape bottom part to pass a belt therethrough; and tying the belt at the waist front part to make the brassiere freely detachable and adjustable or usable without attaching the belt.