A supporting device for a display unit for rotating a display screen to be oriented vertically. The supporting device includes a fixed member mounted on a base, an elevating member secured to the fixed member to be lifted or lowered, a pivot bracket rotatably coupled to an upper end of the elevating member while being secured to a rear surface of the display unit, an operating lever having an upper portion rotatably coupled to the upper end of the elevating member, a holder formed at the fixed member to allow the operating lever to be caught therein when being rotated rearward in a lifted state of the elevating member, a horizontally movable member secured to the upper end of the elevating member, and a cam portion formed at the pivot bracket.