A developer case (10) according to the present invention includes a case main body (30), a rotator (55, 56), a coupling (57), and a holder (49, 70, 80, 90). The case main body (30) contains developer. The rotator (55, 56) is rotatably arranged between a pair of sidewalls (43F, 43B) of the case main body (30). The pair of sidewalls (43F, 43B) are opposed to each other. The coupling (57) is coupled to the rotator (55, 56) with at least one of the pair of sidewalls (43F, 43B) in between. The holder (49, 70, 80, 90) protrudes on an inner face of at least the one of the pair of sidewalls (43F, 43B) and holds an end in an axis direction of the rotator (55, 56) at a position where the end is capable of coupling to the coupling (57).