A tube pump comprising a flexible tube, a pressing member capable of generating a negative pressure in the tube by sequentially pressing the tube from as the pressing member moves from an upstream portion of the tube to a downstream portion of the tube during a pump operating process, a rotating member which includes a cam surface which the pressing member comes in sliding contact with when the pressing member moves between a pump operating position where a negative pressure is generated in the upstream portion of the tube and a pump non-operating position where the negative pressure is not generated, and a rack member including a plurality of teeth, wherein the pressing member is provided with a pinion member capable of continuously engaging with the a flexible portion of the rack member when the pressing member rotatably moves between the pump non-operating position and the pump operating position.