Abstract: A disposable medical support undergarment is provided selectively to cover a groin part and selectively to expose thigh arteries of a patient at angiography operation and detachably attach a portion of the undergarment. The undergarment includes a front center sheet, a back panel and an assistant sheet. The width of the front center sheet is predetermined to cover the groin part of a patient and expose the left and right thigh arteries near the groin part, and the back panel includes a pair of front side sheets and a back sheet integrated with the pair of front side sheets. The side end portion of front center sheet and the side end portion of the front side sheet of the back panel can be detachably attached each other.