To properly pre-cool a refrigerator.SOLUTION: A communication device (2) comprises a pre-cooling determination unit (202) configured to: using any one of a position of a user before increase and a time until articles in a refrigerator (1) increases, at the time when the articles in the refrigerator (1) increases in the past, and a current position of the user, determine whether the user acquires articles to be input to the refrigerator (1); derive an input time until the articles are input to the refrigerator (1); and when the input time is within a first predetermined time, transmit a pre-cooling command for the refrigerator (1).SELECTED DRAWING: Figure 1
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