Optical measurement apparatus

An optical measurement apparatus comprising:

• a light receiving element capable of converting a light intensity of light to be analyzed into an electrical signal;
• an input terminal to which the electrical signal is input;
• a first amplifier and a nonlinear element configuring a logarithmic amplifier, an inverting input terminal of the first amplifier being electrically connected to the input terminal;
• a plurality of offset resistors having resistance values different from each other;
• a switch unit capable of switching an offset resistor to be electrically connected between a voltage source and the input terminal, of the plurality of offset resistors;
• and
• a controller, wherein
• an offset current is input to the input terminal by the offset resistor electrically connected between the voltage source and the input terminal,
• the controller measures the light intensity based on an output voltage value of the logarithmic amplifier, and
• the controller adjusts the offset current by switching the offset resistor to be electrically connected between the voltage source and the input terminal, and is capable of changing a measurement sensitivity of the optical measurement apparatus in stages.