To obtain in high yield a chlorinated organic compound useful as a raw material for medicines, agrochemicals or functional polymers.

This chlorinated organic compound (e.g. cyclobutyl chloride) is obtained by reaction of an alkene [pref. a cyclic alkene of the formula (R1-R3 are each H, a halogen, alkyl, etc.; (n) is an integer of pref. 3-6) such as cyctlopropene] with hydrogen chloride in the presence of a metal halide (e.g. aluminum trichloride) and a protonic polar compound (e.g. water, methanol, 1-butanediol, diethylamine) at 10-30,000ppm based on the alkene.