Pump Unit, Syringe Unit, Method for Delivering Particles, and Method for Delivering Cells

The present invention relates to a pump unit or the like which feeds particles in a liquid with particles dispersed therein to a predetermined area. An object of the present invention is to obtain a sufficient solution feeding resolution while inhibiting mixture of bubbles. The pump unit includes a moving mechanism 13 that moves a pump 12 and a reservoir 11 relative to each other to vary the positional relationship between a tip 1221 of the pump 12 and an edge 112 of the opening 111 between a separating relationship in which the tip 1221 is separated upward from the edge 112 of the opening 111 in a liquid reserved in the reservoir 11 and a pressing relationship in which the tip 1221 is pressed against the edge 112 . In the separating positional relationship, the pump 12 performs a sucking operation to take particles C into its interior. In the pressing relationship, the pump 12 performs an ejecting operation to deliver the particles C. The moving mechanism 13 varies the positional relationship between the separating relationship and the pressing relationship with the tip 1221 immersed in the liquid reserved in the reservoir 11.