普通抵押權以債務關係已成立為前提，最高限額抵押權係就未來發生但不超過一定數額之債權而為擔保，此與一般抵押權發生、移轉、處分及消滅上之從屬不同。我最高法院跟隨德國法制，早承認此制，多年後再正式立法。最高限額抵押權之所謂最高限額乃指債務額加利息及違約金之總合。但在設定抵押權契約之內容確定前，得因當事人同意而變更債權、債務人、債之確定期日及最高限額。一旦最高限額因法律原因確定，即成為具體數額之債權而非不特定之債權。此時債務人自得請求結算實際債權額。並將其登記變為普通抵押權。即時非債務人之抵押人自得於清償最高限額後，請求塗銷抵押權。又最高限額抵押權確定前，縱債務不存在，抵押權仍存在。必須原債權確定後，該抵押權已無擔保債權，最高限額抵押權才消滅。

Contrary to the common notion “No Debt, No Mortgage”, mortgage subject to a ceiling ( hereinafter MSTC ) is established to cover future debts resulting from certain legal relationship, but not exceeding a certain amount. Common mortgage is attached to debt in terms of its existence, transfer, disposal and elimination. The ROC Supreme Court followed German practices in recognizing MSTC long before this institution became part of legislation. Since there is a ceiling agreed upon for MSTC, this ceiling refers to the sum total of debt, interest plus damage for breach of agreement. Before the finalization of contract establishing MSTC, two parties may agree to change the debt content, debtor, date for ascertaining the amount owed and its ceiling. Once the ceiling is finalized through statutory reasons, such obligation would become specific debt obligation. The debtor may certainly request that such debt be put in exact figures and that registration of MSTC be changed to common mortgage in land office. The non-debtor-mortgagor may request that MSTC be cancelled upon having paid off the ceiling which is lower than debt. Finally, mortgage still exists before finalization of MSTC despite non-existence of debt. The elimination of mortgage would not happen until no more debt obligation is attached to the mortgage after the original debt in the MSTC having been finalized.