PURPOSE: To efficiently pattern rubber balloon by vertically oscillating rubber balloon molds formed with rubber films on the surfaces around the axial centers of supporting rods and dropping a colored rubber glue liquid to the surfaces of these rubber films like yarn or rain drops, thereby patterning the rubber balloons.

CONSTITUTION: The supporting rods 7 having the rubber balloon molds 4 at their front ends are freely vertically oscillatably and freely turnably mounted at a chain 1 which is a continuous moving member moving endlessly. The supporting rods 7 are passed through a rubber latex liquid bath according to the movement of the chain, by which the rubber films 3 are formed on the surfaces of the rubber balloon molds 4. A rubber belt 8 which is a regulating means 11 for oscillating the rubber balloon molds 4 while rotating the molds and is wound around a pair of pulleys 9, 10 is disposed on the downstream side in the moving direction of the chain 1. Further, the colored rubber glue liquid 6 is dropped like yarn or rain drops from a rubber glue tank 12 to the rubber films 3. As a result, the spiral patterns 13 and dotty patterns 14 are formed on the surfaces of the rubber films 3.