The information processing device 1D mainly includes a state-of-activity estimation unit 31D and a timing determination unit 32D. The state-of-activity estimation unit 31D estimates, based on information detected in a meeting room in which a meeting is being held, a state of activity of the meeting. The timing determination unit 32D determines a timing of mobile sales of a commodity to one or more participants of the meeting based on the state of activity estimated by the state-of-activity estimating unit 31D.