PURPOSE: To obtain benzhydrols useful as a photo polymerization initiator and a raw material for pharmaceuticals at a low cost in a high yield by reacting an aryl compound with an aromatic aldehyde.

CONSTITUTION: The compound of formula III is obtained by reacting a compound of formula I (R is H or an alkyl; M is an alkali metal; m=1 to 5) with a compound of formula II (X is H, a halogen, a lower alkyl, a lower alkoxy, aryloxy, etc.; n=1 to 5) in a solvent (e.g. toluene) at -50 to 30°C. The compound of the formula I is used in an amount of 1.0-1.5mol based on 1mol of the compound of the formula II. The solvent is used 2-20 times the compound of formula I in weight. The objective compound is useful as a raw material for a pharmaceutical such as an antihistaminic, a vasodilator and an antiallergic.