<p>This paper first makes a novel observation that sluicing in Japanese allows finiteness mismatches. Then, an account of this observation is proposed based on the idea that ellipsis sites can be smaller than usually assumed, which makes it possible to maintain a syntactic identity-based approach to ellipsis mismatches by rendering the mismatches in question as only apparent ones. To be more specific, it is proposed that sluicing can target a <i>v</i>P serving as a direct complement of C, instead of a TP, and that the problems induced by such a structure are essentially morphophonological so that they can be repaired by ellipsis. Then, it is pointed out that the proposed analysis offers a solution to a puzzle hidden under a widely accepted analysis of Japanese sluicing employing cleft structures, which requires Argument Ellipsis targeting a CP to take a TP antecedent. The solution crucially assumes that Argument Ellipsis can target a <i>v</i>P serving as a clausal argument instead of a full-fledged CP, and it is shown that this assumption receives independent support since it offers a unified account for another novel observation indicating that Argument Ellipsis targeting clausal arguments is insensitive to the mismatches regarding the modal particles contained in them.</p>