To provide a stable umbrella structure which can be easily assembled by providing a shank, a lower ring, an upper ring, a stretcher, a rib and a sheet composed of ethylene polyvinyl alcohol(EVA), and slidably arranging the lower ring on an outer periphery of the shank.

All members except for a sheet 6 are formed of resin such as an ABS resin, a polystyrene resin and a polypropylene resin, and the sheet 6 is formed of an EVA film. A lower ring 2 is slidably installed in the vertical direction on the outside of a shank 1, and an upper ring 3 is fixedly installed in an upper part of the shank 1. One end of a stretcher 4 is rotatably installed on the ring 2, and the other end of the stretcher 4 is installed so as to engage with a prescribed part of a rib 5. One end of the rib 5 is rotatably installed on the upper ring 3, and an exposed part 6a of the sheet 6 is fitted in the other end of the rib 5, and a removable cap 10 is installed in an upper part of the upper ring 3 so as to sandwich the sheet 6 between it and the upper ring 3.