To provide a micro screw pump capable of permanently transporting a reagent and improving reaction efficiency of reagents.

This micro screw pump 1a is provided with a cylindrical casing 20, a first port (hollow part 22a and through hole 21a) formed on one end side of a casing 20 and communicating with an inside of the casing 20, a second port (hollow part 23a and through hole 21b) formed on another end side of the casing 20 and communicating with an inside of the casing 20, and a screw shaft member 30 having a screw formed on a circumference surface thereof and rotatably fitted inside of the casing 20. Ratio W/H of groove width W to groove depth H of the screw is 4.33≤W/H≤13.2.