The present invention relates to a tunnel information broadcasting system using speakers for a tunnel that have an improved ability to transmit information. More specifically, the present invention relates to a tunnel information broadcasting system comprising: a plurality of speakers for a tunnel, the speakers being installed along opposite wall surfaces of the tunnel with a predetermined interval therebetween, each speaker having a horn for sound output and installed such that one surface part of the horn adjacent to a tunnel sidewall is in contact with the tunnel sidewall; an amplifier for amplifying sound signals; and a main control unit which delays outputs of the respective speakers for the tunnel that are arranged in the progress direction of a vehicle with respect to the speaker adjacent to the corresponding vehicle. According to the present invention, information can be output as sounds toward a travelling vehicle with a delay using the plurality of speakers for a tunnel, and thus a driver in the vehicle can clearly identify the information, thereby rapidly realizing and responding to the situation.