To provide a soft type toner storage container whose capacity can be decreased as toner is discharged and which can be loaded in an image forming apparatus, without wasting the space thereof, even if the container is full of toner.

The toner storage container comprises a substantially parallelepiped bag 3 fixed to a mouthpiece member 2. The bag 3 has a body 4 and a bottom 5, and the body 4 has a tapered section 6 formed into the shape of a pyramid, and a cylindrical narrow mouth 7 continuing from the leading end of the tapered section 6. The bottom 5 has a bottom crease 8 for folding face members c and d on both sides toward the inside. The body 4 has side creases 11 for folding the upper part 10 of the body 4 toward the inside of the bag 3, leaving the lower part 9; flexible creases 12 for dividing the lower part 9 into halves; and oblique creases 15 and 16, for obliquely folding half lower parts 13 and 14 toward the inside of the bag 3.