An object of the present invention is to provide oysters which are highly safe and not contaminated with microorganisms including 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 the in-season period. Provided is a method for cultivating oysters on land, the method including growing oyster larvae into adult shellfish in seawater containing deep-sea water in a water tank through feeding microalgae cultured in seawater containing deep-sea water to the oyster larvae. Specifically, provided is a method for cultivating oysters on land, the method including growing oysters in a suspension system including seedling collectors suspended vertically or horizontally on ropes by allowing deep-sea water to continuously flow through the system without stagnation or repeatedly allowing deep-sea water to stagnate and continuously flow through the system without stagnation at a given interval at a seawater temperature of 10°C to 30°C for 5 months to 18 months.
