Floating particle detection device

A floating particle detection device comprising:

• a laser light irradiator that includes a laser light emitting element including a front-side edge surface that emits an irradiation laser beam with which a detection-target region where floating particles are present is irradiated and a back-side edge surface that emits a back-monitor-use laser beam which travels in a direction opposite to a travel direction of the irradiation laser beam, and a back-monitor-use light receiving element disposed in a position where the back-monitor-use laser beam is incident, the back-monitor-use light receiving element generating a first detection signal according to an amount of incident light;
• a scattered light receiver that selectively receives light of a predetermined polarization component among scattered light of the irradiation laser beam, the scattered light being generated when a floating particle is irradiated, thereby generating a second detection signal;
• and
• an identification processor that identifies a type of the floating particle on a basis of the first detection signal and the second detection signal;
• wherein the incident light entering the back-monitor-use light receiving element includes the back-monitor-use laser beam and backscattered light travelling toward the laser light irradiator among the scattered light of the irradiation laser beam with which the floating particle is irradiated.