A method and a device for discriminating an obscene video using a time-based feature value are provided. The method includes: forming a first time-based flow of predetermined feature values varying with the lapse of time from one or more types of videos which are normalized with a first time interval; extracting a feature value varying with time from an input video of which obsceneness is to be determined and which is normalized with a second time interval, and forming a second time-based flow of the extracted feature value; and determining the obsceneness of the input video by calculating a loss value between the first time-based flow and the second time-based flow. The videos such as movies and dramas in which many persons appear have different obscenity characteristics from that of pornography, so it is possible to enhance reliability in determination of obsceneness.