To improve adhering strength of a key top to an EL sheet substrate in an interior illuminating type key top device using the EL sheet.

The key top 20 positioned on a light emitting surface side of the EL sheet 10, on which an EL layer 12 is formed on a transparent substrate 11 such as PET film is adhered and fixed by an adhering layer 30 provided with a 2 layer structure consisting of a first layer 31 on the EL sheet side and a second layer 32 on the key top side. The first layer 31 is constituted by adhesive with high adhering force to the EL sheet substrate (PET film)11, and the second layer 31 is constituted by adhesive provided with high adhering force to the key top material.