a monolithic metal structure with each microneedle 52 standing on and perpendicular to the upper surface 511 of supporting pad 51 and a hollow closed tube being formed between top portion 523 523 a and supporting pad 51 fig5 c shows a schematic view of the structure of microneedle array device 50 of the present invention the top portion 523 of each microneedle 52 is a slant and the cross section of tube wall 524 forms a closed oval circular or triangular shape as shown in fig6 a and fig6 b respectively the metal for fabricating microneedle array can be cu cr ni fe au pt pd stainless steel or their alloys the range of the aperture of each microneedle is 10 70 um the outer circumference is 80 250 um and the height is 100 600 um fig7 a 7j show the fabrication method of the first embodiment of the present invention first a substrate is provided including a plurality of concave areas on the surface according to the present invention there are several techniques for forming a plurality of concave areas including etching x ray photo etching ultra violet etching ion beam etching and excimer laser micromaching the present embodiment uses.