An electromagnetic wave detector provided with a first electromagnetic wave sensor that has a light reception unit held in midair above a substrate by a support leg and a second electromagnetic wave sensor that has a light reception unit held in midair above the substrate by a support leg having the same structure as the support leg of the first electromagnetic wave sensor and is provided so as to be adjacent to the first electromagnetic wave sensor, said electromagnetic wave detector being characterized in that the light reception unit of the first electromagnetic wave sensor has a reflective film, the light reception unit of the second electromagnetic wave sensor has an electromagnetic wave absorption body for detecting light of a prescribed wavelength band or a prescribed polarization, and the difference between the output of the second electromagnetic wave sensor and the first electromagnetic wave sensor is output.