钻机是在地表进行钻洞的机械设备，可以是大型户外的水井、油井、天然气井钻探设备，或者是单人可移动的小型设备，称为螺旋钻。钻机可以对地下矿藏进行取样，或者用于安装地下生产设备，例如地下机器、仪器、管道和井道。可以是安装在卡车、拖车、轨道上的移动设备，或者是较为固定的安装在陆地、海上结构（如钻井平台，一般称为“海上石油钻机”，尽管设计上并不含有钻机）。“钻机”这个词一般指钻探地球的地壳层的设备。

钻机包括：

A drilling rig is a machine that creates holes in the earth sub-surface. Drilling rigs can be massive structures housing equipment used to drill water wells, oil wells, or natural gas extraction wells, or they can be small enough to be moved manually by one person and are called augers. Drilling rigs can sample sub-surface mineral deposits, test rock, soil and groundwater physical properties, and also can be used to install sub-surface fabrications, such as underground utilities, instrumentation, tunnels or wells. Drilling rigs can be mobile equipment mounted on trucks, tracks or trailers, or more permanent land or marine-based structures (such as oil platforms, commonly called 'offshore oil rigs' even if they don't contain a drilling rig). The term "rig" therefore generally refers to the complex of equipment that is used to penetrate the surface of the Earth's crust.