To obtain the subject compound for providing a high-purity metallocene compound in a high yield, by reacting an organomagnesium compound with a cyclopentadienyl compound in a noncyclic ether solution, removing the noncyclic ether from the reaction mixture and treating the resultant substance with a cyclic ether.

An organomagnesium compound of the formula RMgX (R is a hydrocarbon; X is a σ bonding ligand) (e.g. methylmagnesium chloride) is reacted with a cyclopentadineyl compound (preferably cyclopentadiene) in a noncyclic ether solvent (preferably diethyl ether). The noncyclic ether is removed from the reaction mixture and the resultant substance is treated with a cyclic ether (preferably tetrahydrofuran) to give the objective compound of the formula CpMgX(L)n (Cp is cyclopentadienyl, indenyl, etc.; L is a cyclic ether; (n) is a real number of 0-2).