In order to enable, even when an increased number of workers become analysis targets, efficient analysis on work efficiency statuses of workers without putting a greater burden on an administrator to perform setting operations for the analysis, analytical information is produced by performing a joint position estimation based on respective frames of video recordings to estimate joint positions of a worker, performing a posture match determination based on results of the joint position estimation to determine whether or not to achieve a posture match between a posture of the worker in each frame of the video recordings and a predetermined reference body posture, and measuring, based on results of the posture match determination, a working time and a presence time of the worker used as analytical information on a work efficiency status of the worker.