NEW MATERIAL: An oxadiazolone compd. represented by formula I (wherein R1 is alkoxycarbonylalkyl).

EXAMPLE: 5-t-Butyl-3-(2-fluoro-4-chloro-5-(1-ethoxycarbonyl)ethoxy)phenyl)-1,3,4- oxadiazol-2(3H)-one.

USE: A herbicide showing especially high selectivity to a soybean, wheat and barley.

PROCESS: A compd. represented by formula II and a compd. represented by the formula: R1-Y (Y is an elimination group) are reacted in a solvent such as acetone or acetonitrile in the presence of a base such as an alkali metal carbonate, alkali metal hydroxide, alkali metal alkoxide or the like to obtain the compd. represented by formula I.