An X-ray image capturing apparatus includes: scanning and signal lines； an X-ray sensor； detecting elements； a switching element to make charges accumulated in response to an OFF voltage and released in response to an ON voltage； a scan driving unit to switch a voltage applied to the scanning lines between ON and OFF voltages； a readout circuit to read the charges as image data； and a control circuit to detect an irradiation start by a first scheme based on a current increase due to X-ray irradiation or a second scheme based on an output from the X-ray sensor and to turn off the switching element to make charges accumulated if the first or second scheme detects the irradiation start, wherein a detection threshold is set such that the second scheme has a slower response and can detect an X-ray at a lower dose rate than the first scheme.
