It is an object of the present invention to allow a cell to produce a protein at a high level using a medium containing an enzymatic degradation product of fish meat or a fish meat extract. A method of culturing a cell comprising starting culturing in an initial medium and feeding at least once a feed medium to the initial medium during culturing, wherein at least one of the initial medium or the feed medium contains an enzymatic degradation product of fish meat or a fish meat extract added thereto. A method of producing a protein of interest using the above culture method.
