Thats the brake vacuum pump, the power steering pump is on the top left.
The leak you have is common,but could be 2 possibles
The gaskets have had a design change as the old ones did suffer poor sealing and the pump it self has been known to fail.
pump failures have arisen from a leaking front seal and also a distorted sealing face (where it goes on the gasket)
it's an easy repair which takes less than an hour, but a new pump is over 120 quid
hope that helps.