缢蛏（学名：Sinonovacula constricta）为竹蛏科缢蛏属的动物，俗名青子、蛏子。

长形两端圆的外壳，壳顶靠近前方；生长线显着，原本黄绿色壳面常磨损脱落而呈白色。

Sinonovacula constricta, the constricted tagelus, Chinese razor clam or Agemaki clam is a commercially important species of bivalve native to the estuaries and mudflats of China and Japan. It is extensively aquafarmed in China and other countries, with 742,084 tons worth US$667,876,000 harvested in 2008.