Support device for protecting window glass

Provided is a support device (100) for protecting window glass, which can easily be attached to and detached from the window glass and can prevent the window glass from breaking by evenly distributing wind pressure imparted to the window glass. The support device (100) for protecting window glass comprises: a main body (50) for supporting the window glass; a plurality of extension belts (60) which extend radially from the main body, each with a first end detachably fastened thereto; and suction plates (159) constituted at each of the other ends of the extension belts. The main body (50) for supporting the window glass has: a first member (10) which is height adjustable and to which the ends of each of the plurality of extension belts are fastened; and a suction plate (21) of a second member (20) which is provided on a surface on one side of the first member, and is constituted so as to make contact with the window glass.