A cancellation is thought to be a basic process of the photospheric magnetic field and plays an important role in magnetic flux budget and in various solar activities. There are two major theoretical scenarios for this phenomena, the "U-loop emergence" and the "Ω-loop submergence" models. It is important to clarify which is the dominant process during the cancellation for the estimation of the solar magnetic flux transport through the surface. We study the vector magnetic field and velocity structures around a quiet-Sun cancellation by using the Solar Optical Telescope on board the Hinode satellite. Transverse magnetic field connecting the canceling magnetic features and strong long-lasting Doppler redshift signal are found. The transverse field is observed in the first spectropolarimetric observation after the occurrence of the cancellation while the redshift is clearly delayed to the cancellation by 20 minutes. These results indicate that the observed cancellation is an "Ω-loop submergence."