Optical detection device and signal processing method

An optical detection device comprising:

• a first photoelectric conversion element configured to output a first output when the first photoelectric conversion element is irradiated with a light pulse;
• and
• a second photoelectric conversion element configured to output a second output when the second photoelectric conversion element is irradiated with the light pulse, wherein
• the optical detection device is configured to combine a first signal caused by the first output with a second signal caused by the second output when the first photoelectric conversion element and the second photoelectric conversion element are irradiated with the same light pulse, in a state where a first condition and a second condition are satisfied,
• the first condition is a condition that an absolute value of an amount of change until the first signal reaches a peak is different from an absolute value of an amount of change until the second signal reaches a peak, and
• the second condition is a condition that a sign of the amount of change until the first signal reaches the peak is different from a sign of the amount of change until the second signal reaches the peak.