To provide a tool for squeezing out the content of a flat bag to use the content by a safe and simple procedure from opening to squeezing out while easily maintaining hygienic cleanness without the risk of causing a burn by heat and also without waste regardless of whether the amount of the content is large or small.

The tool for squeezing a flat bag is characterized by: (α) having a squeezing section which has either U-shape or V-shape with a root closed and a top opened and is closed tightly at the top by grasping with hands; (β) squeezing out by pushing the content forward by setting the squeezing section gradually narrower toward the reverse direction to the direction of the content squeezing out: (γ) having the squeezing section which has been processed by either antisepticising or anti-fouling or both antisepticising and anti-fouling; and (δ) performing in a series from opening to squeezing of the content with a means equipped at a part of the squeezing section for opening the flat bag.