To prevent the light transmissivity of a light transmission part from being impaired, and the shadow of the opaque resin of a character part from transmitting to the light transmission part.

By this method, a number plate main body has a character part 3 punched, and a character made of synthetic resin having an opaque colored character part 41 in a specific character shape and a light transmission part 42 which is provided around the character part 47 and has the same color with the number plate main body surface is fitted in the character part 3 and bonded by thermocompression on the reverse surface of the number plate main body, thus manufacturing the letter illuminating license plate. In this case, the character part 41 has a character part main body 411 in a specific shape and a character thermocompression bonding leg part 412 drooping from the character main part main body 411 and the light transmission part 42, on the other hand, is equipped with a light-transmissive thermocompression bonding leg part 422 drooping from the light transmission part main body 421 similarly and a fitting-in hole 423 in which the character thermocompression bonding leg part 412 is fitted; and the character thermocompression bonding leg part 412 and light-transmissive thermocompression bonding leg part 422 are at a specific interval and forms a pool part 43.