Microfluidic device and sample analysis method

A microfluidic device comprising:

• a base plate having a first composition and allowing an electromagnetic wave having a wavelength to pass through the base plate, the based plate including a material suppressing auto-fluorescence from excitation by the electromagnetic wave having the wavelength;
• a microwell array formed on the base plate and including a wall layer, the wall layer including a plurality of through-holes formed in a thickness direction of the wall layer to form microwells;
• and
• a lid member disposed over an opposite side of the microwell array opposite to a base plate side of the microwell array facing the base plate, the lid member disposed to be in a state of being separated from the wall layer, wherein
• bottoms of the microwells are constituted by the base plate,
• sidewalls of the microwells are constituted by the wall layer,
• the microwells are open toward the lid member,
• the through-holes as the microwells are configured to hold a reagent, and
• the wall layer having a second composition different from the first composition, the wall layer having the second composition including a resin and a particle-shaped component which absorbs an electromagnetic wave of a same wavelength as a fluorescence wavelength of a fluorescence emitted from the reagent.