Abstract: Novel ergoline derivatives and acid addition salts thereof are disclosed. These ergoline derivatives possess excellent anti-hypertensive activity, vasodilating activity, anti-ulcer activity, gastric secretion inhibitory activity, brain metabolism improving activity, anti-depressive activity and dopamine-like activity, and, therefore, are useful for prevention and treatment of various diseases such as hypertension, a wide variety of vein disorders, peptic ulcer, brain absormality, depression, Parkinson's disease, high prolactin blood disease, etc.