Cartridge, detection method, and detection device

A cartridge for detecting a target substance, comprising:

• a chamber configured to accommodate a sample containing the target substance, the chamber comprising:
• a first region comprising a closed space at an outward side of the cartridge;
• a second region disposed at a position closer to a center of the cartridge than the first region;
• and
• at least two protrusions protruding inward inside the chamber from a position between the first region and the second region toward a centerline of the chamber, and located at positions facing each other in a circumferential direction of the cartridge, wherein the centerline of the chamber runs in a radial direction outward from the center of the cartridge though a center of the chamber, wherein the radial direction is orthogonal to the circumferential direction,
• wherein a first side surface of each of the at least two protrusions on a side further from the center of the cartridge and a second side surface of each of the at least two protrusions on a side closer to the center of the cartridge are angled toward each other to form tips of the at least two protrusions,
• wherein the second region is connected to a flow path and includes protruding regions protruding outward on both sides in the circumferential direction of the flow path and away from the centerline of the chamber, and
• wherein a boundary between the first region and the second region is defined as a line extending between the tips of the at least two protrusions.