The invention relates to an information transmission system capable of transmitting target information via voice, as well as to an information encoding apparatus and an information decoding apparatus for use with the system. The information encoding apparatus (31) converts input text information to an intermediate code in accordance with a predetermined encoding method, and outputs a voice derived from voice information based on the intermediate code and supplemented with music arrangement information. The voice is transmitted either directly or via a broadcasting or communicating medium to a receiving side. The information decoding apparatus (34) on the receiving side receives the generated voice, recognizes a voice waveform from the received voice, and reproduces the original target information by decoding the intermediate code based on the recognized voice waveform. During the encoding, the intermediate code is assigned to at least one element of the voice, and the music arrangement information is used as a basis for determining at least one other element of the voice. This provides the kind of voice agreeable to the human ear.