PURPOSE: To keep the excellent appearance and electrical characteristic of an antenna for a long period of time and also to reduce the cost and the manufacturing period of the antenna by applying the coating on the surface on a plate type antenna substrate excluding its both ends which are connected to a printed board.

CONSTITUTION: An insulated material of high heat resistance and high hardness is applied on the entire surface of an antenna substrate 102 including its outer surface and excluding its both end parts 101 which are connected to the circuits of a printed board. In, other words, the parts 101 are masked by taping, etc., and an antenna 10 is totally put into a bath containing the fused insulated material such as epoxy resin, nylon resin, etc., for coating. Otherwise the heated antenna 10 is put in an atmosphere where the insulated material is turned into the fine powder, and this powder attached on the antenna surface is welded. Thus a silver plated layer 103 is formed on the surface of the substrate 102, and furthermore an insulated layer 104 is formed on time entire surface of the substrate 102 excluding both parts 101. As a result, the antenna 10 of such a constitution is obtained.