1. A container having a mouth portion forming, on the outer circumferential surface thereof, a screw thread for fastening a cap, wherein a horizontally recessed portion which is arcuate or annular is formed between the upper end of said screw thread and the upper end of said mouth portion or in said screw thread, and the angle θ of the upper wall surface of said horizontally recessed portion is set to be 80 degrees to 150 degrees relative to the vertical direction.

2. The container according to claim 1, wherein said angle θ is set to be 90 degrees to 150 degrees.

3. The container according to claim 1, wherein said horizontally recessed portion is formed between the upper end of said screw thread and the upper end of said mouth portion, said horizontally recessed portion being annular in shape, and said angle θ being set to be 90 degrees to 150 degrees.

4. The container according to claim 1, wherein the distance from the upper wall surface of said horizontally recessed portion to the upper end of said mouth portion is in a range of 1 to 2 mm.

5. The container according to claim 1, wherein the depth of said horizontally recessed portion is in a range of 0.2 to 1.5 mm.

6. The container according to claim 1, wherein said container is made of a plastic material.

7. The container according to claim 6, wherein said container is used for containing non-carbonated beverages.

8. The container according to claim 6, wherein said container has the mouth portion formed in white color, and is used for containing colored liquids.