A retractable bimini top device is disclosed for automated operation and mounted attachment to an existing rooftop member set over the deck of a boat. The inventive device includes a U-shaped support frame having respective side legs adapted to travel longitudinally through a pair of housing tube members disposed in parallel and mounted beneath the rooftop member. The side legs of the U-shaped frame are coaxially fitted within the housing tube members and made to travel together in unison through the respective tube members, each upon a lead screw that is driven by a reversible motor electrically powered and mounted at the end of each tube. A canvas cover attached along its outer end to the transverse portion of the U-shaped frame is stored in a rolled-up state about a spring-loaded roller mounted transversely between the housing tube members so that the canvas cover may be extended in a substantially horizontal manner and retracted as the side legs of the support frame are moved in alternate linear directions through the housing tube members.