A communication terminal operating with electric power stored in a battery to execute information communication with an external communication device is provided. The communication terminal repetitively acquires specific information including a present position of the communication terminal and transmits the specific information in a transmission period. The communication terminal includes a detection section for detecting a total number of external communication devices present within an area of a pre-specified distance and a setting section for setting the transmission period in accordance with the total number of external communication devices detected by the detection section.