A packet analysis method includes acquiring a first acknowledge packet and a second acknowledge packet transmitted from the first device; acquiring a plurality of packets transmitted from the second device during a period from reception of the first acknowledge packet to reception of the second acknowledge packet; identifying a number of packets corresponds to data transmitted from the second device, by calculating a difference between a first identification number corresponding to the first acknowledge packet and a second identification number corresponding to the second acknowledge packet; calculating a plurality of bandwidth values, a number of the plurality of bandwidth values is identical to the number of packets, based on acquisition timings of the plurality of packets and an interval between the acquisition timings of two adjacent packets; and determining a bandwidth value that is to be removed from the plurality of bandwidth values by comparing the plurality of bandwidth values.