A method for extracting differentiated cells from a cell population comprising undifferentiated cells after induction of the differentiation of pluripotent stem cells. A method for extracting differentiated cells from a cell population, comprising the following steps: (1) a step of introducing, into a cell population, mRNA comprising a marker gene operably linked to the target sequence of miRNA specifically expressed in pluripotent stem cells; and (2) a step of extracting cells in which the marker gene has been translated.