To provide an upper guide device for sliding door capable of moving together with a door panel and extending only when a sliding door is opened and supporting an upper part of the door panel so as not to tilt forward and backward.

An upper part of a door panel 1 is guided by utilizing an expandable beam. The expandable beam consists of a guide frame 7 fixed on an upper outer face of an opening frame 6, a slide frame 8 fixed on an upper end face of the door panel 1, and a play beam 9 connecting both frames 7, 8. An upper slide body 22 slide-guided in a face-contact manner by the guide frame 7 is provided on one side of an upper face of the play beam 9. A slider 24 slide- guided in a line-contact manner by the slide frame 8 is provided on the other side of a lower face of the play beam 9. An opening contact tool which comes into contact with the slider 24 and operates it together during opening of the door panel 1 is provided on the slide frame 8. In the same way, a closing contact tool which operates the slider 24 together during closing of the door panel 1 is provided on the slide frame 8.