In the south-western sea of Suonada, it has been reported that oxygen consumption in the sea water might be induced by the resuspension of the bottom mud. Therefore we tried elucidating the resuspension process of the bottom layer by the field-experiments using the mooring system at a fixed observation point over a fortnight of the late summer in 2005 and 2007. The analysis of the observational data has revealed that the non-periodic current was generated rather strongly at the neap tide although the induced current was periodic around the spring tide. Resuspension due to tidal currents was recognized well around the spring tide while it was never observed at the neap tide even if the current was large. Resuspension around the spring tide was caused quarter-diurnally in phase of the current speed in 2005. However, it was caused semi-diurnally in 2007, and it was observed only at the flood flow.