A radiographic image capturing apparatus includes: scanning and signal lines; a two-dimensional array of detecting elements defining a detecting part; a control unit that reads image data from all detecting elements in a reading area of the detecting part by repeating a cycle of a readout process at N-line intervals, wherein the scanning line subjected to the readout process is shifted every cycle, where N is an integral number of at least 1; and a communication unit for external communication. The control unit detects a radiation emission start of a radiation irradiating apparatus, and if the readout process starts with an N+1th or any subsequent scanning line and then starts with any of first to N+1th scanning lines in a certain cycle, the control unit transfers the image data read in the certain cycle as preview image data substantially concurrently with the readout process.