Detection device and detection method

A detection method for detecting a detection target substance by using a metal material modified with a first substance having a property of specifically binding to the detection target substance and a fluorescent material modified with a second substance having a property of specifically binding to the detection target substance, the detection device method comprising:

• emitting light for exciting the fluorescent material;
• detecting fluorescence emitted by the fluorescent material over time for a specific period from when emission of the light is stopped;
• and
• detecting the detection target substance in a complex formed of the metal material, the detection target substance, and the fluorescent material binding to each other, on the basis of an attenuation characteristic of the fluorescence during the specific period.

A detection device comprising:

• a light source that emits light to a sample liquid containing a fluorescent material modified with a second substance;
• a photodetector that detects an intensity of fluorescence emitted by the fluorescent material excited by the light, for a specific period after emission of the light is stopped;
• and
• a processor that determines whether the sample liquid contains a detection target substance on the basis of the detected intensity, wherein
• the detection target substance directly binds to the second substance, and the detection target substance binds to a metal material with a first substance therebetween.