An electromagnetic wave sensor includes a substrate having transmittance of electromagnetic waves having a specific wavelength, an insulator layer provided on one surface side of the substrate, a thermistor film disposed to have a space between the thermistor film and one surface of the substrate, and a wiring part provided inside or on a surface of the insulator layer and electrically connected to the thermistor film, wherein a transmittance of the electromagnetic waves at a portion facing the thermistor film is relatively higher than a transmittance of the electromagnetic waves at a portion where the wiring part is provided in a layer in which the insulator layer is provided.