The purpose of the present invention is to provide oysters that are highly safe and that are not contaminated by microorganisms such as viruses and bacteria, the oysters moreover being fresh and having high nutritional value, and being available throughout the year in the same state as oysters from in-season periods. Provided is a method for cultivating oysters on land, the method comprising feeding microalgae cultured in seawater that includes deep-sea water to oyster larvae, and using seawater that includes deep-sea water to grow the oyster larvae into adult shellfish in a water tank. Specifically, provided is a method for cultivating oysters on land, the method comprising growing the oysters at a seawater temperature of 10-30°C for five to 18 months in a suspension scheme in which cultch is suspended horizontally or vertically on ropes, growth being carried out by allowing deep-sea water to flow in the suspension scheme or by repeatedly causing water to stagnate and flow in the suspension scheme for given periods of time.
