(Introduction) There are various odors for our circumference. And it is well known that the brain is kept exciting after olfactory sensor does not feel odor stimulus. (Purpose) Various odors exist in the hospital, so it needs simple structure machine, which decomposes odor by easy operation. We make attention to the titanium oxide which has photochemical reaction by ultraviolet light. (Method) We used ultraviolet LED of center wavelength 380nm, and irradiated on surface painted titanium oxide. We quantified decomposition of various chemical substance with a glass gas detector tube. (Results) We applied 12[V] to 21 LEDs and attached fan to small box. We put ammonia, alcohol, acetic acid, isovaleric acid into large (40[L]) vessel which this box was operated. Each substances became less concentration that human was not able to feel less than 20 minutes. We recognized that odor material was decomposed by several times of circulation when we thought about fun flow. (Conclusion) We used photochemical reaction by the titanium oxide as a method to easily decompose odor. We were able to decompose to level not to feel by voltage of 12[V] within approximately 20 minutes.