An image forming apparatus to which a toner container is detachably mountable includes a mounting portion to which the toner container is detachably mountable and which includes a receiving port for receiving toner supplied from the toner container, a passage for permitting passing of the toner received through the receiving port and provided with a through hole, and a filter portion provided so as to cover the through hole and for permitting passing of air; and an accommodating portion configured to accommodate the toner received through the receiving port. At least a part of the through hole overlaps with the receiving port as viewed in a horizontal direction perpendicular to a direction of gravitation.