Signal processing device for x-ray analysis

Provided is a signal processing device for X-ray analysis capable of suppressing effects of increased background due to pile-up signals and suppressing the dead time from lengthening. A signal processing device for X-ray analysis includes a differentiating circuit configured to convert a plurality of staircase wave signals detected by the X-ray detector into differential wave signals, a digital filter configured to convert the differential wave signals into trapezoidal wave signals or triangular wave digital signals, and a peak detection unit configured to discriminate and count a peak value extracted from a peak portion of the trapezoidal wave signal or the triangular wave signal. The peak detection unit is set such that a rising threshold Tu to be compared with a signal of the rising-side sloped line segment and a falling threshold Td to be compared with a signal of the falling-side sloped line segment in the trapezoidal signal or the triangular wave signal have a relation of Tu>Td. The peak detection unit selects the trapezoidal signal or the triangular wave signal to be counted from the converted trapezoidal signal or the converted triangular wave signal based on the rising threshold Tu, and terminates detection of the peak portion of the trapezoidal signal or the triangular wave signal based on the falling threshold Td.