The present invention provides a method that allows highly efficient and highly reliable evaluation of genomic stability of pluripotent stem cells, a method for removing pluripotent stem cells that have been identified as genomically unstable by the evaluation method from a culture of pluripotent stem cells to be evaluated, and a synthetic peptide that can be used for the methods. The methods provided by the present invention include preparing a culture of pluripotent stem cells of interest and analyzing an expression level of calreticulin for the pluripotent stem cells in the culture followed by identifying genomic stability or genomic instability of the stem cells on the basis of the expression level of calreticulin.