PURPOSE: To eliminate drop in traveling of irradiation light by preventing adhesion of reaction products in photoinductive chemical reaction using a mixed solution prepared enough to cause a reaction.

CONSTITUTION: An alkaline alcohol solution 1 mixed with a polychlorobiphenyl is irradiated with a laser light 4 to cause a photoinductive chemical reaction. In other words, the solution is turned to a fast fluid and then, flows into a reactor 3. This eliminates retention of polluting substances after the photoinductive reaction, otherwise blocking transmission of light, in a laser light irradiation area 6 thereby allowing the reaction solution 7 and reaction products 8 to flow down to a post-treatment solution recovery pipe 9 from the reactor 3.