A developing apparatus includes a developing container for containing a developer; a developer carrying member to be rotated while carrying the developer thereon, the developer carrying member being provided in an opening portion of the developer container; and a sealing member which extends in a circumferential direction of the developer carrying member in the vicinity of an end of the developer carrying member and regulates movement of the developer toward the end of the developer carrying member by a magnetic force, the sealing member including an arcuate portion extended along a peripheral surface of the developer carrying member and a non-arcuate portion disposed at an end, in the circumferential direction, of the arcuate portion. An end surface of the arcuate portion of the sealing member on a side where the non-arcuate portion is not provided, is inclined such that a phantom plane including the end surface is closer to the arcuate portion than a center of arcuation of the arcuate portion.