A rainwater guiding device for a meteorological observation balloon for preventing the observer and electronic devices held by the observer from getting wet by rainwater by guiding the rainwater flowing down along the surface of the balloon to the outside of the observer's workspace during the rawinsonde levitation operation for upper atmospheric observation, wherein the rainwater guiding device is composed of a double-cone structure comprising an inner cone closely contacted with the surface of the balloon around the inlet and an outer cone formed on the outside of the inner cone, wherein the inner cone and the outer cone have funnel shapes, each of which has a conical portion at the upper portion as a shape gradually widening in the upward direction, and an extension portion at the lower portion extending vertically downward from a neck portion, which is a neck portion below the conical portion.