A content playback information estimation apparatus for use on a networked system in which a distribution server distributes content such as video content in packets to a playback terminal for storing and playing the content, the content playback information estimation apparatus being configured to estimate a playback halt state of content data in the terminal, the content playback information estimation apparatus comprising: a packet information obtaining unit configured to obtain packet information contained in packets sent and received via the network; a buffer parameter estimation unit configured to estimate a buffer parameter based on the packet information, a content received amount estimation unit configured to estimate, for each one of a plurality of time points, the amount of content data received in the playback terminal based on the packet information; a playback start time estimation unit configured to estimate a time period required for starting playback in the playback terminal by using the amount of content data estimated by the content received amount estimation unit; a playback state estimation unit configured to estimate, by using the amount of content data estimated by the content received amount estimation unit and the buffer parameter estimated by the buffer parameter estimation unit, whether a state in the playback terminal is in a playback state or in a halt state at each time point based on a data amount that is consumed by a playback application of the playback terminal at each time point after start of playback; and a playback halt time estimation unit configured, when the playback state estimation unit determines the state is in the halt state, to estimate a time point at which playback is halted and a length of the halt, wherein the playback terminal stores the content data in a playback buffer, starts playback when content data of an initial buffer amount is stored in the playback buffer, reads data required for playback from the playback buffer during playback, halts playback when a buffer amount stored in the playback buffer falls below a playback halt threshold, and starts playback when the buffer amount stored in the playback buffer exceeds a playback start threshold; and wherein the playback state estimation unit is configured to perform processes, at each time point, for increasing, by the amount of received content data, the estimated amount of content that is stored in the buffer and decreasing, by the amount of data consumed by the playback application, the estimated amount of content that is stored in the buffer, to determine that the state changes to the halt state when the estimated amount of content that is stored in the buffer falls below the playback halt threshold in the playback state, and to determine that the state changes to the playback state when the estimated amount of content that is stored in the buffer exceeds the playback start threshold in the halt state in which the data amount consumed by the playback application is 0. a packet information obtaining unit configured to obtain packet information contained in packets sent and received via the network; a buffer parameter estimation unit configured to estimate a buffer parameter based on the packet information, a content received amount estimation unit configured to estimate, for each one of a plurality of time points, the amount of content data received in the playback terminal based on the packet information; a playback start time estimation unit configured to estimate a time period required for starting playback in the playback terminal by using the amount of content data estimated by the content received amount estimation unit; a playback state estimation unit configured to estimate, by using the amount of content data estimated by the content received amount estimation unit and the buffer parameter estimated by the buffer parameter estimation unit, whether a state in the playback terminal is in a playback state or in a halt state at each time point based on a data amount that is consumed by a playback application of the playback terminal at each time point after start of playback; and a playback halt time estimation unit configured, when the playback state estimation unit determines the state is in the halt state, to estimate a time point at which playback is halted and a length of the halt, wherein the playback terminal stores the content data in a playback buffer, starts playback when content data of an initial buffer amount is stored in the playback buffer, reads data required for playback from the playback buffer during playback, halts playback when a buffer amount stored in the playback buffer falls below a playback halt threshold, and starts playback when the buffer amount stored in the playback buffer exceeds a playback start threshold; and wherein the playback state estimation unit is configured to perform processes, at each time point, for increasing, by the amount of received content data, the estimated amount of content that is stored in the buffer and decreasing, by the amount of data consumed by the playback application, the estimated amount of content that is stored in the buffer, to determine that the state changes to the halt state when the estimated amount of content that is stored in the buffer falls below the playback halt threshold in the playback state, and to determine that the state changes to the playback state when the estimated amount of content that is stored in the buffer exceeds the playback start threshold in the halt state in which the data amount consumed by the playback application is 0.