<p>The present invention relates to a serum-free medium for culturing animal cells which contains soybean protein hydrolysate and yeast extract; a method for culturing animal cells which comprises a step of culturing animal cells in the serum-free medium; and a method for producing a desired substance which comprises a step of culturing animal cells in the serum-free medium, causing the desired substance to be produced by and secreted out of the animal cells and a step of isolating the desired substance from the serum-free medium.</p>