A method for distinguishing living cells in a living state with high accuracy. A method for distinguishing a desired cell type from a cell group comprising two or more types of cells, using the expression of miRNA as an indicator, wherein the method comprises the following steps: (1) a step of introducing mRNA comprising a marker gene operably linked to the target sequence of miRNA used as an indicator into a cell group; and (2) a step of distinguishing a cell type, using the translation level of the marker gene as an indicator.