In a liquid supply apparatus, plungers which respectively expand and contract pump chambers are reciprocated linearly in an axial direction with their phases shifted to each other, thereby continuously discharging liquid. In a pump block, drive rods are mounted so as to be reciprocatable in an axial direction. At a center in an axial direction of shafts attached to the drive rods, drive rollers are mounted, and rollers are mounted at both ends of the shafts. Guide grooves which support the guide rollers are formed in guide blocks.