A developing device includes a developer carrying member for developing an electrostatic image with a developer, a developer container including a developer accommodating portion, a developing opening, and a developing chamber, and a developer supplying member that includes a shaft member, a first feeding member, and a second feeding member. The first feeding member has a length L1 measured in an axial direction of the developer carrying member and has a rotational radius R1 measured from a rotation center of the shaft member, and the second feeding member has a length L2. When a length of the developing opening is L3, a shortest length from the developing opening to the shaft member is L4, and a length from the developer carrying member to the shaft member is L5, the following relationships are satisfied: L1