This invention relates to a nanowire-assisted method for mass spectrometric analysis of a specimen. More specifically, by using nanowire which can fix a specimen and perform desorption/ionization of the specimen while effectively transferring laser energy to the specimen to be irradiated, thereby enabling to perform mass spectrometric analysis without using a matrix solution. This invention, by effectively performing desorption/ionization of a specimen using the above-mentioned nanowire, enables to effectively perform qualitative-, quantitative-, and micro-analyses of specimens as well as low molecular weighted specimens. Further, this invention enables to the typical device of mass spectrometric analysis used in MALDI-T of MS. In particular, this invention can perform mass spectrometric analysis of a specimen with molecular weight of less than 1,000 Da and perform quantitative analysis by fixing a specimen with a predetermined area.