This invention provides a multipolar cell including three or more centrosomes dispersed therein and a multipolar spindle formed so as to extend from the three or more respective centrosomes. The multipolar cell production method provided by the present invention supplies cultured eukaryotic cells with a synthetic peptide as a multipolarity-inducing peptide, with the synthetic peptide having an amino acid sequence selected from SEQ ID NO: 1 to SEQ ID NO: 12 or an amino acid sequence formed by substituting, deleting and/or adding one, two or three amino acid residues in/from/to the selected amino acid sequence.
