In an electromagnetic wave generation device including a plurality of electromagnetic wave generation elements, an instantaneous maximum power consumption during an electromagnetic wave generation operation is reduced. Specifically, the electromagnetic wave generation device includes a plurality of electromagnetic wave generation elements that are divided into a plurality of groups, and a control unit that causes the plurality of electromagnetic wave generation elements to oscillate while shifting a timing in units of group. For example, the control unit causes the plurality of electromagnetic wave generation elements to oscillate such that when the number of the plurality of groups is n, an oscillation start timing of the group that performs mth oscillation (m is a natural number equal to or larger than 2 and equal to or smaller than n) is the same timing as or after an oscillation end timing of the group that performs (m−1)th oscillation.