A method for preparing animal cells with good adhesion and proliferation properties which are capable of proliferation is provided. the method permits the detachment of cultured cells without damaging the cells. A method for preparing a sheet of animal cells such as skin cells which are capable of proliferation is also provided. A method for preparing animal cells capable of proliferation, comprising the steps of (1) culturing animal cells on a substrate at least one portion of which is an electrode, and (2) applying a high-frequency wave potential to the electrode to detach the cells that have adhered to the substrate surface through culturing. The high-frequency wave potential is of a frequency falling within a range of 1 KHz to 10 MHz with a potential falling within a range of ± 1.0 V (vs. Ag/AgCl) or less. The culture medium during separation does not contain calcium or magnesium.