To simplify the structure of a fluid force feeding device.

This device is equipped with a rotational shaft horizontally journalled in the center of it and provided with rotation driving force, and three disk cams 5A, 5B, 5C which are respectively eccentrically fixed to this rotational shaft 6 and are rotated by rotation driving force provided for the rotational shaft, each of total six plunger bodies 3, 3... removable to profile curves of the cams is arranged on each of both radial sides of the disk cams 5A, 5B, 5C such that their axial line direction is horizontal and orthogonal to the rotational shaft 6, the plunger bodies 3, 3... are respectively energized by energizing means S, S... so as to come into contact with the profile curves of the disk cams 5A, 5B, 5C, the tips of the plunger bodies 3, 3... are respectively placed in cylinders 4, 4... and suction passages 7, 7... and delivering passages 8, 8... are connected with the inside of the cylinders 4, 4....