PURPOSE: To obtain the titled compound economically in high yield, by saponifying an aqueous solution of an olefin chlorohydrin with carbide waste while introducing steam into the reaction liquid using a multi-stage column reactor having weeping plates.

CONSTITUTION: An olefin oxide useful as a raw material of various chemicals is produced in high efficiency, at a low cost, from acetylene waste obtained at a large quantity as an industrial waste of acetylene industry, by saponifying an aqueous solution of an olefin chlorohydrin with a carbide waste while introducing a large amount of steam into the reaction liquid using a multistage column reactor wherein the reaction zone is composed of weeping plates. The tray of the above weeping plate is preferably a seep tray having a mesh diameter of 3W 20mm and areal ratio of 20W60%. The reaction is distributed over a multiple stages, and a satisfactory yield can be attained even by using carbide waste as the saponifying agent.