To provide a rain umbrella storage bag leaking no raindrop and easily and repeatedly allowing accumulated raindrops to be drained and an umbrella to be inserted and removed by fitting and fixing a raindrop outflow preventing tool combined with a cap, a pipe fixing a packing, and the packing at the lower end of the bag kept with the upper section of a sewn section at the open state.

A raindrop outflow preventing tool is fitted and fixed to an umbrella storage bag kept with the upper section of the bag at the open state. The raindrop outflow preventing tool is provided with a cap applied with a female screw 20 on the inside of a shallow cylinder made of a thin iron sheet, bored with a hole 21 to be inserted with the shaft tip of an umbrella at the center of a ceiling section on the upper surface of the cylinder, and carved with a fine, shallow, circular, recessed groove 22 for depressing a packing from the outside on the surface of the ceiling section of the cylinder between the outer periphery of the hole 21 and the outer edge of the cap. The raindrop outflow preventing tool is provided with a pipe applied with a male screw 23 on the outside of the pipe made of a resin, keeping its upper end 24 horizontal, and fixing a packing having a knob 25 at the lower end. The raindrop outflow preventing tool is also provided with the packing bored with a hole 26 to be inserted with the shaft tip of the umbrella at the center of a thin disk made of high-elasticity rubber.