A radiological image-capturing device includes: a first read control section that executes a first read mode in which electric signals stored in a plurality of pixels are read out simultaneously in units of a plurality of rows； and an emission-start determining section that determines that the emission of radiation from a radiation source onto an image-capturing panel has started when the values of the electric signals read by the first read control section have become greater than an arbitrarily settable threshold. If it is determined by the emission-start determining section that the emission of the radiation has started, the first read control section terminates the reading of the electric signals, and thereby brings the image-capturing panel into an exposure state.
