A fluid delivery apparatus comprises a first piston body, a second piston body, a fluid delivery pipe, and a sealing element. The first piston body has a first through hole, a first connecting portion, an accommodation space and a buffer space. The second piston body has a second through hole and a second connecting portion disposed inside the accommodation space. The fluid delivery pipe is accommodated in the first through hole and the second through hole, and movable between a first position and a second position. The sealing element encircles the fluid delivery pipe. When the fluid delivery pipe is at the first position, the sealing element is accommodated in the accommodation space. When the fluid delivery pipe is at the second position, a first part of the sealing element is accommodated in the accommodation space, and a second part of the sealing element is accommodated in the buffer space.