A measurement device includes: a capturing part for causing a liquid to capture detection target particles contained in a gas and causing a fluorescent substance specifically bondable to the detection target particles to be bonded to the detection target particles; a droplet forming part for forming aerosol-like droplets from the liquid; and a measurement part for irradiating light onto the droplets and measuring the fluorescence intensity of the droplets. The capturing part includes a cyclone which swirls the gas introduced from a gas introduction part in a circumferential direction, separates the detection target particles toward a wall surface of the cyclone body under a centrifugal force, introduces the liquid from the liquid introduction part, causes the liquid to capture the detection target particles separated toward the wall surface and continuously supplies the liquid to the droplet forming part.