An X-ray exposure control device which is configured to be used in an X-ray image detection apparatus (14, 102, 122) to detect an X-ray image of a radiography target exposed to X-ray radiation from an X-ray source and which is configured to control an accumulated dose of the X-ray radiation received by the radiography target, the X-ray exposure control device comprising: an X-ray detection element (18, 18a, 18b, 18c) including a plurality of pixels for dose detection (76, 76a) each detecting a dose during the X-ray radiation; a region setting unit configured to set a use pixel region including pixels for use in dose detection from the plurality of pixels for dose detection during the X-ray radiation; a storage unit which is configured to read out the dose detected by each of the plurality of pixels for dose detection in the X-ray detection element at each preset sampling timing during the X-ray radiation, obtain the accumulated dose by accumulating the dose detected and read out at each preset sampling timing, and store the accumulated dose as dose information; a signal generating unit configured to read out the accumulated dose from the storage unit, compare the accumulate dose with a threshold preset and generate successive radiation signals for radiating the X-ray from the X-ray source until the accumulated dose has reached or exceeded the threshold; and a transmission unit configured to continuously transmit to the X-ray source the successive radiation signals for radiating the X-ray as generated by the signal generating unit, wherein the X-ray source is configured to stop the X-ray radiation when the reception of the successive radiation signals is stopped, wherein the region setting unit is configured to identify subject pixels representing the radiography target constituting a subject or pixels within a radiation field exposed to the X-ray radiation by combining a plurality of pixel characteristics and neighboring pixel characteristics from dose information of the plurality of pixels for dose detection, and set the use pixel region to contain the subject pixels or the pixels within the radiation field as the pixels for use in the dose detection. an X-ray detection element (18, 18a, 18b, 18c) including a plurality of pixels for dose detection (76, 76a) each detecting a dose during the X-ray radiation; a region setting unit configured to set a use pixel region including pixels for use in dose detection from the plurality of pixels for dose detection during the X-ray radiation; a storage unit which is configured to read out the dose detected by each of the plurality of pixels for dose detection in the X-ray detection element at each preset sampling timing during the X-ray radiation, obtain the accumulated dose by accumulating the dose detected and read out at each preset sampling timing, and store the accumulated dose as dose information; a signal generating unit configured to read out the accumulated dose from the storage unit, compare the accumulate dose with a threshold preset and generate successive radiation signals for radiating the X-ray from the X-ray source until the accumulated dose has reached or exceeded the threshold; and a transmission unit configured to continuously transmit to the X-ray source the successive radiation signals for radiating the X-ray as generated by the signal generating unit, wherein the X-ray source is configured to stop the X-ray radiation when the reception of the successive radiation signals is stopped, wherein the region setting unit is configured to identify subject pixels representing the radiography target constituting a subject or pixels within a radiation field exposed to the X-ray radiation by combining a plurality of pixel characteristics and neighboring pixel characteristics from dose information of the plurality of pixels for dose detection, and set the use pixel region to contain the subject pixels or the pixels within the radiation field as the pixels for use in the dose detection.