圣玛莉艾克斯30号（30 St. Mary Axe） 是位处英国金融重镇伦敦市的一栋摩天大楼，暱称小黄瓜（Gherkin），正式名称为「瑞士再保险公司大楼」（the Swiss Re Building）。1996年，崔佛嘉集团提出一份建造伦敦千禧塔的计划，预计兴建一栋总高度386公尺，总楼层面积9万平方米，并含有一座305公尺观景台的摩天大楼。然而，此计划因为遭到反对而作罢，取而代之并获得许可的是原计划的更新版本──改为建造一座高度较低的大楼，也就是现在的圣玛莉艾克斯30号大楼。

圣玛莉艾克斯30号落成于2003年12月，并于2004年4月28日启用。这栋大楼有180公尺高，共40层。它的建造象征着伦敦新一波高楼热的兴起。大楼的命名起自它的地址，也就是建筑物所在的“圣玛莉艾克斯”或斧头圣玛莉街，而30则为其门牌号码。

30 St Mary Axe (widely known informally as The Gherkin and previously as the Swiss Re Building) is a commercial neo-futuristic skyscraper in London's primary financial district, the City of London. It was completed in December 2003 and opened in April 2004. With 41 storeys, it is 180 metres (591 ft) tall and stands on the former sites of the Baltic Exchange and Chamber of Shipping, which were extensively damaged in 1992 by the explosion of a bomb placed by the Provisional IRA in St Mary Axe, the street from which the tower takes its name.