Method and device for modifying fluororesin

The invention provides an improved fluororesin modification method and an improved fluororesin modification device. The modification method of the fluororesin comprises two processes. In a first step, a first gas including an organic compound containing oxygen atoms is irradiated with ultraviolet light having an intensity in a wavelength region of at least 205 nm or less, and the first gas irradiated with the ultraviolet light is brought into contact with a fluororesin. In the second step, a second gas containing oxygen molecules is irradiated with the ultraviolet light, and the second gas irradiated with the ultraviolet light is brought into contact with the fluororesin. The modification device is provided with at least one gas supply port for supplying a first gas containing an organic compound containing oxygen atoms and a second gas containing oxygen molecules, and a light source for irradiating ultraviolet light having an intensity in a wavelength region of 205 nm or less toward the supplied first gas an