  The identity of dark matter has been a mystery in astronomy, cosmology, and
particle theory for about a century. Bessho, Ikeda, and Yin (2022), three of
the current authors, proposed using the state-of-the-art infrared
spectrographs, including WINERED at $6.5$m Magellan Clay telescope and NIRSpec
at James Webb Space Telescope, as efficient detectors for the indirect
detection of dark matter with the mass around eV by measuring the line photons
from the dark matter two body decays. Applying this concept, we have performed
spectrographic observations of dwarf spheroidal galaxies (dSphs) Leo V and
Tucana II using WINERED by utilizing an object-sky-object nodding observation
technique for background subtraction. We present the first result from this
dark matter search. Employing zero consistent flux data after the sky
subtraction, we have established one of the most stringent limits to date on
dark matter decaying into line photons in the mass range of $1.8-2.7\,$eV. Our
data can also be applied to constrain other spectra of photons from the dSphs.
