An information terminal sequentially transmits one or more packets to an information distribution server, receives acknowledgments for the transmitted packets from the information distribution server, and records a round trip time and occurrence of packet loss for each of the transmitted packets. Among one or more packet sequences, the information terminal counts the number of packet sequences which are such that the number of packet losses included in each of the packet sequences and an increase state of the round trip time for packets included in the packet sequence satisfy respective predetermined conditions. Each of the one or more packet sequences has multiple continuous packets including one or more packets, for which packet loss is recorded among the transmitted packets, at the top. The information terminal calculates a packet loss ratio on the basis of the counted number and the number of transmitted packets.