There is disclosed a stamp pad unit (1), in particular for a self-inking stamp, which comprises two ink pads (2a, 2b) being arranged within a frame (3), abutting against opposing surfaces (4a, 4b) of a separating plate (5) and being separated thereby from each other, wherein the frame (3) consists of two separate frame parts (3a, 3b) which are connected with each other and within which the ink pads (2a, 2b) are accommodated, wherein at least one frame part (3a, 3b), preferably each of the frame parts (3a, 3b), comprises at least one inwardly directed retaining projection (6a, 6b) engaged with an ink pad (2a, 2b) for holding the ink pad (2a, 2b).