Photodetection device and photodetection system

A photodetection system comprising:

• a light-emitting section that emits light;
• and
• a photodetector that detects light reflected by a detection object of the light emitted from the light-emitting section, wherein
• the photodetector includes a light-receiving section that includes a light-receiving element, and generates a pulse signal including a pulse corresponding to a result of light reception by the light-receiving element,
• a plurality of switches that is each turned on or off on a basis of a corresponding control signal of a plurality of control signals, and each transmits the pulse signal by being turned on in a pulse period of the corresponding control signal of the plurality of control signals,
• a plurality of counters that is provided corresponding to the plurality of switches, and each performs counting processing on a basis of the pulse signal supplied through a corresponding switch of the plurality of switches to generate a first count value, and
• a signal generator that generates the plurality of control signals in a detection period to sequentially shift the pulse period of the corresponding control signal of the plurality of control signals by a unit period having a shorter time length than the pulse period.