Fortescue Metals Group's chief financial officer Stephen Pearce will leave the iron ore company at the end of the year to join global miner Anglo American as its finance director.

Since he joined the company in 2010, Mr Pearce has helped steer Fortescue through a phase of rapid growth before leading the drive to lower its costs and slash its heavy debt pile during a period of weakness in iron ore prices, reducing its gross debt to about $US6 billion from a peak of $US12.7 billion in 2012.