A radiographic imaging device including: a detector that detects an irradiation start of radiation irradiated in imaging of a radiographic image; a derivation unit that derives an irradiation amount of radiation that will be irradiated within a specific period of time based on input data; a controller that makes a power supply amount to the detector smaller and lowers detection sensitivity to radiation irradiation start in the detector the larger the radiation irradiation amount derived by the derivation unit; and an imaging unit that images the radiographic image after radiation irradiation start has been detected by the detector.