Assay apparatus and cartridge

An assay apparatus used for immunochromatographic assay, the assay apparatus comprising:

• a loading part in which a cartridge is loaded, where the cartridge includes a carrier having an assay region in which a color development state changes depending on whether a sample is positive or negative, and a case in which the carrier is accommodated in an inner space defined by an outer shell formed of a translucent material and in which an opening portion for observing an observation region including the assay region is formed in a part of the outer shell;
• an illumination unit that has an emission end portion for emitting light that illuminates the observation region, where the illumination unit makes it possible to dispose at least a part of the emission end portion in a state of being brought into contact, in a position separated from the opening portion on an outer surface of the outer shell of the cartridge in a loaded state, the position being capable of guiding a light incident into the outer shell from the emission end portion to an inner edge of the opening portion by transmitting the incident light through the outer shell;
• and
• a detection unit that is disposed at a position facing the opening portion of the cartridge in a loaded state and detects a color development state of the assay region, where the detection unit optically detects the color development state by receiving a reflected light which is emitted from an inner edge of the opening portion and reflected by a surface of the observation region.