We investigated photo flow bromoallylation of alkynes and alkenes using a photo reactor MiChS L-1S and UVLED (MiChS UV-LED-S). Flow bromoallylation of alkynes proceeded well with a residence time of 10 or 20 min, which considerably shortened the reaction time of the batch reaction (Xe irradiation for 12 h). Bromoallylation of alkenes was also successful using the same photo flow protocol.