PURPOSE: To prevent deformation of a blade rubber by sending air from a compressor to a flat tube having a wiper blade at the front surface fixed to a wire installation metal, expanding the tube, and protruding the blade from a protective pin for protecting the blade.

CONSTITUTION: Air from a compressor is injected from an air injection port 2 to expand a tube 1 formed like a flat bag, which returns to be flat by removing the air, and when the tube 1 is expanded, the forward end part of a wiper blade 3 gets in contact with a glass surface to wipe raindrops, etc. A moulded base part 5 at the back surface of the tube 1 can be engaged with a groove 7 moulded at the front surface of a wiper installation metal 6, and a protective pin 9 composed to cover the blade 3 when the tube 1 is not expanded, and curved toward the blade 3 to protrude the blade 3 forward when it is expanded, is inserted in a box-like blade protective pin inserting part 8. Deformation of a blade rubber can thus be prevented.