PURPOSE: To provide a method for producing 9-methylfluorene by which the production can industrially be carried out at a low cost.

CONSTITUTION: This method for producing 9-methylfluorene is to react biphenyl with an ethynylating agent or ethylbiphenyls in the presence of an acidic catalyst, produce ethylbiphenyl and 9-methylfluorene, respectively cut the contents of 4-ethylbiphenyl to ≤5wt.% and diethylbiphenyl having ethyl group at the o-position to ≤5wt.% and raise the 9-methylfluorene purity to ≥90wt.% by distillation or the distillation and crystallization. Thereby, the 9-methylfluorene useful as an intermediate for various precision chemicals can efficiently be produced at a low cost and the method is industrially significant.