An over-the-top type cabinet door prop unit is characterized in that it comprises a fitting case to be rigidly fitted to the inner surface of one of the lateral walls of the cabinet, a movable spring holder vertically movable relative to the fitting case containing it and urged downward by compression springs, a link arm pivotably linked at the upper end to the movable spring holder by a pivot pin and a swing arm swingable around an arm spindle located in a lower portion of the fitting case and having a base section arranged around the arm spindle and linked to the lower end of said link arm by a link pin and an arm section extending from the base section and pivotably linked at the distal end thereof by an anchor pin to an anchor pin bearing secured to the over-the-top type cabinet door and that the pivot where the link arm and the base section of the swing arm is linked by the link pin is located closer to the cabinet door relative to the vertical axial line connecting the pivot pin and the arm spindle when the over-the-top type cabinet door is closed and moved onto the vertical axial line in the initial stages of the opening motion of the cabinet door and then further away from the cabinet door relative to the vertical axial line in the subsequent stages of the opening motion of the cabinet door until the cabinet door is placed on the top wall of the cabinet.