According to the invention, a pull-down signal detecting apparatus includes: an interfield motion detecting module configured to determine whether or not an interfield motion between a first field signal and a second field signal exists by comparing a first counted number with a first threshold; an interframe motion determining module configured to determine whether or not an interframe motion between the first field signal and a third field signal exists by comparing a second counted number with a second threshold; a determination module configured to determine whether or not the video signal is pull-down signal based on the determination result of the interfield motion determining module and the interframe motion determining module; and a threshold control module configured to vary the first threshold, when the determination result of the interframe motion determining module corresponds with a second pull-down pattern and when the determination result of the interfield motion determining module does not correspond to a first pull-down pattern.