Optical concentration measuring device and signal processor

An optical concentration measuring device comprising:

• a light source configured to emit light toward a gas detection space into which a gas to be detected is introduced;
• a detector configured to detect a signal, based on at least a portion of the light that was emitted from the light source and passed through the gas to be detected, and output a detection signal;
• a signal processor configured to acquire the detection signal and convert the detection signal to a digital signal;
• and
• a substrate on which the detector and the signal processor are provided, wherein
• the detector comprises a first detector and a second detector,
• the signal processor is configured to form a terminal array in which a plurality of signal terminals is sandwiched between a plurality of voltage terminals, the signal terminals being input and output terminals of signal lines electrically connected to the detector, the voltage terminals supplying a constant voltage other than 0 V and not being electrically connected to the detector,
• the plurality of voltage terminals comprises a first voltage terminal, a second voltage terminal, and a third voltage terminal, and
• in plan view of the substrate from a front, the signal processor and a wiring connecting the first voltage terminal and the second voltage terminal surround signal lines connecting the first detector and the signal processor, and the signal processor and a wiring connecting the second voltage terminal and the third voltage terminal surround signal lines connecting the second detector and the signal processor.