房宿四 (β Sco / 天蝎座β) 是天蝎座的一个恒星系统，俗名Acrab、Akarb或Elacrab，都来源于阿拉伯语(阿拉伯语：العقرب‎) al-'Aqrab，即蝎子，对整个星座的统称。同时它也和天蝎座Xi共用一个名字Graffias。在中文里，房宿四是房宿的第四星。

用小型望远镜观看，可以发现房宿四是一个由相距14弧秒、实际距离至少2200天文单位的两颗成员星组成的双星系统。二者均为灼热的光谱型为B型的恒星，质量至少为太阳的10倍，其寿命会太阳短。预计二者都会以超新星爆炸的形式结束它们的进化历程。

Beta Scorpii (β Sco, β Scorpii) is a multiple star system in the southern zodiac constellation of Scorpius. It has the traditional names Acrab, Akrab or Elacrab, all come from (Arabic:العقرب‎) al-'Aqrab, the Scorpion, for the whole constellation, as well as Graffias, a name it shares with Xi Scorpii. It was known as 房宿四 (the Fourth star of the Room) in Chinese.