A non-transitory computer-readable storage medium storing therein a packet analysis program for causing a computer to execute a process comprising detecting, from a plurality of received ACK packets, a successive ACK packet group including a plurality of ACK packets for which each reception interval is smaller than a first reference value and in which a round-trip time of each ACK packet becomes shorter in order of reception, and estimating wireless quality based on the number of ACK packets constituting the successive ACK packet group.