Abstract: "Gutter Jack" is a mechanical device which is temporarily attached to the facia board at the end of the roof to support and to adjust the slope of the rain gutter during the installation. A gutter jack is generally used at each end of the rain gutter to be installed or at an intermediate position as required. The gutter jack includes a base mounting plate which is temporarily attached to the facia board and an adjustable Z-Bar bracket which supports the rain gutter and sets the slope. The Z-Bar bracket is easily adjusted and locked in position by loosening and re-tightening wing nuts.