An X-ray detection signal processing device (10) and the like according to the present invention includes: a comparator (17) configured to output a High signal when a level of a signal from a continuous reset type preamplifier (13) having an CR circuit (13a) does not exceed a predetermined upper limit value, and output a Low signal when the level of the signal from the preamplifier (13) exceeds the predetermined upper limit value; and a control section (18) configured to delay shift of the signal of the comparator (17) from Low to High by a predetermined time, to perform output to a clock oscillator (15), stop oscillation by outputting a Low signal to the clock oscillator (15), and thus stop high-speed AD conversion by a high-speed AD converter (14) and maintain an output value.