An irradiator that emits electromagnetic waves through a lattice-like or net-like protective member, and a controller that causes the irradiator to irradiate an irradiation target with the electromagnetic waves while causing relative movement between the irradiation target and the irradiator in a first direction. The protective member is configured or disposed such that no more than one lattice of a plurality of lattices and no more than one node of a plurality of nodes that are formed in the protection member exist in a row along the first direction.