The present invention is directed to a photodynamic therapeutic light irradiation device that irradiates two different light wavelength regions to each other on the irradiated surface. Even if the irradiated surface has irregularities, the irradiated surface has uniform illuminance. It is an object of the present invention to provide a light irradiation device for photodynamic therapy, which can irradiate light and obtain a highly uniform spectral distribution over the entire irradiated surface. The light irradiation device for photodynamic therapy of the present invention is a light source unit in which one or more LED elements that emit first light having a peak wavelength in a range of 400 nm to 420 nm are arranged on a flexible substrate. And a fluorescent plate that transmits part of the first light from the light source unit and converts part of the first light into second light having a wavelength of 500 nm or more and 520 nm or less and emits the same. Features.
