PROBLEM TO BE SOLVED: To achieve adjustment of a schedule across a plurality of calendar systems.SOLUTION: A schedule adjustment device includes: a plurality of proxy access sections 130 which have access to each of a plurality of calendar systems 200; a request reception section 110 which receives a setting request of a schedule including information specifying participation request users who requests participation to the schedule and required time for participation to the schedule; a calendar system specifying section 122 which specifies a calendar system 200 in which schedule data of each of the participation request users included in the setting request is stored; and a schedule adjustment section 121 which selects a proxy access section 130 for getting access to the specified calendar system 200, gets access to the calendar system 200 through the selected proxy access 130 and selects a candidate for the schedule including information concerning the date on which the participation request user can participate.SELECTED DRAWING: Figure 2COPYRIGHT: (C)2021,JPO&INPIT