An electromagnetic wave irradiation device includes an irradiator which irradiates electromagnetic waves onto a liquid droplet which has been adhered to a recording medium, an irradiation controller which causes the irradiator to irradiate the electromagnetic waves periodically such that a frequency of an irradiation period in which the electromagnetic waves are irradiated is a predetermined frequency, and a time setting unit which sets a time ratio obtained by dividing a length of an irradiation time by the irradiator in the irradiation period by a length of a termination time during which the electromagnetic waves are not irradiated by the irradiator in the irradiation period to be a value of greater than or equal to 0.2 and less than or equal to 2.
