Abstract: A microneedle array device and its fabrication method are provided. The microneedle array device comprises a supporting pad and a plurality of microneedles. Each microneedle has a top portion with a via thereon, thereby the microfluid may flow in or out. The intersection between the top portion and the inner tube of a microneedle forms a convex needle structure, and is almost perpendicular to the upper surface. For each microneedle, a hollow closed tube is formed between the top portion and the supporting pad. The fabrication method uses substrates with high transmittance and a plurality of convex area thereon as upper and lower caps, and applies a photolithography process to fabricate a microneedle array mold. It then sputters or electroplates metal material on the mold. The microneedle array is formed after having taken off the mold.