A photocoupler output signal receiving circuit that is configured to receive an output signal of a photocoupler, wherein, in said photocoupler, a signal output from a light emitting unit is transmittable to a light receiving unit in an isolated state, and a pull-up resistor (R pu) is connected to the output side of the light receiving unit, the output signal receiving circuit being characterized by comprising: a first constant current circuit, connected between an input terminal into which the output signal is input and the high potential side of a direct current power source, that is adapted to discharge current to the light receiving unit; a second constant current circuit, connected between the input terminal and the low potential side of the direct current power source, that is adapted to take in current from the direct current power source; and switching elements (NM1-NM3) that are adapted to operate the first and second constant current circuits in a complementary way, wherein, after turning on of the photocoupler, at least two switching elements (NM1-NM2) for operating the first constant current circuit are adapted to be switched from on to off, and at least one switching element for operating the second constant current circuit is adapted to be switched from off to on, and wherein, after turning off of the photocoupler, said switching elements (NM1-NM2) for operating the first constant current circuit are adapted to be switched from off to on, and said switching element for operating the second constant current circuit is adapted to be switched from on to off, and one of the switching elements (NM1-NM2) for operating the first constant current circuit is adapted to be switched off after elapse of a predetermined period after the turning off of the photocoupler for reducing a discharge current value in a current discharge period. a first constant current circuit, connected between an input terminal into which the output signal is input and the high potential side of a direct current power source, that is adapted to discharge current to the light receiving unit; a second constant current circuit, connected between the input terminal and the low potential side of the direct current power source, that is adapted to take in current from the direct current power source; and switching elements (NM1-NM3) that are adapted to operate the first and second constant current circuits in a complementary way, wherein, after turning on of the photocoupler, at least two switching elements (NM1-NM2) for operating the first constant current circuit are adapted to be switched from on to off, and at least one switching element for operating the second constant current circuit is adapted to be switched from off to on, and wherein, after turning off of the photocoupler, said switching elements (NM1-NM2) for operating the first constant current circuit are adapted to be switched from off to on, and said switching element for operating the second constant current circuit is adapted to be switched from on to off, and one of the switching elements (NM1-NM2) for operating the first constant current circuit is adapted to be switched off after elapse of a predetermined period after the turning off of the photocoupler for reducing a discharge current value in a current discharge period.