Provided is an instrumentation device having a pulse output function capable of preventing breakage of a switching element from occurring even in a case of wrong wire connection. A calculation unit (1) includes: a positive power supply terminal (2); a negative power supply terminal (3); a signal terminal (4); a control circuit (6); an NPN-type transistor (7); a feedback circuit (8); a PTC thermistor (9); and an N-channel type MOSFET (10). The NPN-type transistor (7) has a collector terminal connected to the positive power supply terminal (2), an emitter terminal connected to the negative power supply terminal (3), and a base terminal connected to the control circuit (6). The PTC thermistor (9) is a resettable protection element, and is connected in series to the signal terminal (4). The N-channel type MOSFET (10) has a drain terminal connected to the signal terminal (4) through the PTC thermistor (9), a source terminal connected to the negative power supply terminal (3) on a downstream side of the feedback circuit (8), and a gate terminal connected to the control circuit (6).