We present the results of multi-wavelength analysis of 1.2 mm continuum sources detected by ASAGAO. We find that 67 out of 598 ASAGAO sources (S/N > 3.5) have K-band counterparts. Their median redshift is z = 1.83, which is consistent with results of faint (sub-)millimeter sources. Although they mainly lie on the high-mass end of main sequence of star formation galaxies, they show different dust properties from ALMA non-detected sources in ASAGAO field. We also find significant sources (S/N > 5) without K-band counterparts. They can represent the early phase of formation of massive galaxies and non-negligible contributors to the cosmic SFRD.