To provide a straw holder of beverage container capable of storing a straw inside the beverage container at the time of not using it and automatically making the straw jump out and making the straw usable when a cap is detached at the time of restarting drinking.

The thin plastic body whose dimension is smaller than the inner diameter of the cap of the beverage container and is larger than the inner diameter of a drinking port is provided with a helical cut 2, the outer peripheral edge of the plastic body is turned to a locking port edge part 1 and a helical, thin and long part between the cuts 2 is turned to an elastic body 3. A hole 4a for inserting the straw is provided on the center part of the plastic body and a straw holding part 4 provided with small projections 4b from the hole peripheral edge of the hole 4a to the center is formed.