This invention pertains to a windshield wiper blade apparatus for a motor vehicle that more effectively and perfectly completely clears away rainwater or and foreign objects, which stick to on the car windshield, with more definite contact force and without shaking. AlsoFurthermore, this invention more definitely clearly improves the organic coupling structure of the components that constitute the blade apparatus. More specifically, the blade (300) is inserted into the blade couplingblade-couplingunit (10) that is fixed to the rail spring (100); the clamp (400) is coupled to the rail spring (100) through four hook project ions (132) that are formed in the rail spring. The clamp has four coupling protrusions (410) in its lower part, and each coupling protrusion has a hook hole (411) HenceTherefore, the coupling protrusions (410) hook holes (411) hook grooves (131) and hook projections (132) form the clamp-coupling unitpart (130); the spoiler has multiple clip installation sections (210) with grooves for to prevention of the spoilerit from breaking away (211) on its both sides. The clips for to prevention of the spoiler fromit breaking away (220) are inserted into the clip installation sections, The clips are to prevent the spoiler from breaking away by pressing holding the spoiler and part of the rail spring up and downtogether.