1. An information processing apparatus, comprising: an input unit configured to input a plurality of temporally continuous images taken by an image pickup apparatus; an attention object detection unit configured to detect an attention object as an attention target from a first image which is an image taken at a first time point out of the plurality of images input; and a calculation unit configured to compare the first image with one or more second images which are one or more images taken at a time point previous to the first time point, to calculate, as a second time point, a time point when the attention object appears in the continuous plurality of images.