A tool box includes a body with drawers and the body is rotatably connected to a base. A brake unit is received in the base and includes a first board fixed to the base and a second board movably located on the first board by connection plates pivotably connected between the first and second boards. A brake disk is rotatably located on the first board and the shaft is securely connected to the brake disk so that the brake disk is co-rotated with the body. The second board is controlled to move and contact the brake disk on the first board by a clutch pedal. When the second board contacts the brake disk, the body together with the base is moved as one piece, and when the second board is disengaged from the brake disk, the body can be rotated independently relative to the base.