A developing apparatus comprising: a developing container configured to accommodate a developer containing toner and carrier; a developer carrying member rotatably supported by said developing container to carry the developer to a position for developing an electrostatic latent image formed on an image bearing member ; a regulating portion provided opposed to said developer carrying member with a space therebetween to regulate an amount of the developer carried on said developer carrying member ; and a magnet fixed inside of said developer carrying member and having a plurality of magnetic poles (N1, N2, N3, S1, S2) to generate a magnetic field for said developer carrying member to carry the developer, wherein said plurality of magnetic poles (N1, N2, N3, S1, S2) include a developer regulation pole (N1) provided at a position opposed to said regulating portion , wherein in a rotational direction (b) of said developer carrying member , a half-peak center portion position is at a center of a half-peak width of a magnetic flux density distribution of said developer regulation pole (N1) in a normal direction component relative to said developer carrying member , characterized in that said developer regulation pole (N1) is formed such that, in the rotational direction (b) of said developer carrying member , the half-peak center portion position is not less than 3° upstream of a maximum peak position at which a magnetic flux density of said developer regulation pole (N1) in the normal direction component relative to said developer carrying member is maximum, and in the rotational direction (b) of said developer carrying member , a position at which said developer carrying member is closest to said regulating portion is downstream of a position at which a magnetic flux density of said developer regulation pole (N1) in a tangential direction component relative to said developer carrying member is zero. a developing container configured to accommodate a developer containing toner and carrier; a developer carrying member rotatably supported by said developing container to carry the developer to a position for developing an electrostatic latent image formed on an image bearing member ; a regulating portion provided opposed to said developer carrying member with a space therebetween to regulate an amount of the developer carried on said developer carrying member ; and a magnet fixed inside of said developer carrying member and having a plurality of magnetic poles (N1, N2, N3, S1, S2) to generate a magnetic field for said developer carrying member to carry the developer, wherein said plurality of magnetic poles (N1, N2, N3, S1, S2) include a developer regulation pole (N1) provided at a position opposed to said regulating portion , wherein in a rotational direction (b) of said developer carrying member , a half-peak center portion position is at a center of a half-peak width of a magnetic flux density distribution of said developer regulation pole (N1) in a normal direction component relative to said developer carrying member , characterized in that said developer regulation pole (N1) is formed such that, in the rotational direction (b) of said developer carrying member , the half-peak center portion position is not less than 3° upstream of a maximum peak position at which a magnetic flux density of said developer regulation pole (N1) in the normal direction component relative to said developer carrying member is maximum, and in the rotational direction (b) of said developer carrying member , a position at which said developer carrying member is closest to said regulating portion is downstream of a position at which a magnetic flux density of said developer regulation pole (N1) in a tangential direction component relative to said developer carrying member is zero. <EOS>