A developer storage container comprising: a developer storage portion that stores a developer and has an opening for supplying said developer to outside; an agitating-and-supplying member (43, 243, 343, 443) rotatably provided in said developer storage portion, said agitating-and-supplying member (43, 243, 343, 443) having a shaft portion (43a, 343a) and an agitating portion (43b, 243b, 343b, 443b), said agitating portion (43b, 243b, 343b, 443b) having a fixed end and a distal end opposite to each other, said fixed end of said agitating portion (43b, 243b, 343b, 443b) being fixed to said shaft portion (43a, 443a), wherein said agitating portion (43b, 243b, 343b, 443b) has an area (KA 1) corresponding to said opening; wherein, in said area (KA 1), a dimension of said agitating portion (43b, 243b, 343b, 443b) between a center axis of said shaft portion (43a, 343a) and said distal end of said agitating portion (43b, 243b, 343b, 443b) in a direction perpendicular to a center axis of said shaft portion (43a, 343a) is longer than a distance between said center axis of said shaft portion (43a, 343a) and an outer wall of said developer storage portion in said direction perpendicular to said center axis; a part (43b 1, 243b 1, 343b 1, 443b 1) of said agitating portion (43b, 243b, 343b, 443b) in said area (KA 1) configured to protrude outside said developer storage portion via said opening, when in a position facing the opening, and characterized in that: said part (43b 1, 243b 1, 343b 1, 443b 1) of said agitating portion (43b, 243b, 343b, 443b) in said area (KA 1) comprises an inclined portion on a side of said part, configured so that a length of said part (43b 1, 243b 1, 343b 1, 443b 1) of said agitating portion (43b, 243b, 343b, 443b) in said area (KA 1) in a direction parallel to said center axis is shorter at said distal end than at said fixed end. a developer storage portion that stores a developer and has an opening for supplying said developer to outside; an agitating-and-supplying member (43, 243, 343, 443) rotatably provided in said developer storage portion, said agitating-and-supplying member (43, 243, 343, 443) having a shaft portion (43a, 343a) and an agitating portion (43b, 243b, 343b, 443b), said agitating portion (43b, 243b, 343b, 443b) having a fixed end and a distal end opposite to each other, said fixed end of said agitating portion (43b, 243b, 343b, 443b) being fixed to said shaft portion (43a, 443a), wherein said agitating portion (43b, 243b, 343b, 443b) has an area (KA 1) corresponding to said opening; wherein, in said area (KA 1), a dimension of said agitating portion (43b, 243b, 343b, 443b) between a center axis of said shaft portion (43a, 343a) and said distal end of said agitating portion (43b, 243b, 343b, 443b) in a direction perpendicular to a center axis of said shaft portion (43a, 343a) is longer than a distance between said center axis of said shaft portion (43a, 343a) and an outer wall of said developer storage portion in said direction perpendicular to said center axis; a part (43b 1, 243b 1, 343b 1, 443b 1) of said agitating portion (43b, 243b, 343b, 443b) in said area (KA 1) configured to protrude outside said developer storage portion via said opening, when in a position facing the opening, and