A developing device includes: a developer carrying member; a magnet; a developing chamber; a blade member; and a guiding portion. A distance from a developer feeding start position of the guiding portion to said blade member is 2 mm or more along a developer carrying member rotational direction. When a magnetic force at a surface of the developer carrying member with respect to a direction normalto the developer carrying member is Fr, the magnetic poles are provided so that a ratio of an integrated value FrNear obtained by integrating the magnetic force Fr from the blade member to a positionof 2 mm upstream of the blade member with respect to the rotational direction to an integrated value FrAll obtained by integrating the magnetic force from the blade member to the developer feeding start position with respect to the rotational direction is 60% or more.