A fluid infuser includes an introduction needle having a projection on a peripheral surface, and an infusion tube configured to cover the introduction needle. The projection of the introduction needle is installed at a position where the introduction needle comes into contact with the infusion tube, and includes a first surface and a second surface. The first surface is arranged at a picking end side of the introduction needle with respect to the second surface, and an angle of inclination of the first surface is larger than an angle of inclination of the second surface. The fluid infuser is configured to guide an infusion tube to an object of insertion adequately, and allow the introduction needle to be pulled out easily from the infusion tube.
