This thesis aims to discuss the heroic and the monstrous aspects of Beowulf. In the heroic part, I will discuss Beowulf as a culture hero and a mythological hero; in the monstrous part, I will discuss Beowulf as a monster-man and monsters as man-monsters. Beowulf is about a hero who intends to prove himself by killing malicious monsters. The victory over the villains further brings Beowulf the character to the Geatish throne, though Beowulf¡¦s obsession with glory finally results in the fall of his kingdom. Beowulf¡¦s rise represents the rise of the Geatish kingdom and meritocracy; and his fall also triggers the fall of the kingdom. Beowulf¡¦s journey to the Danish kingdom also resembles Joseph Campbell¡¦s theories of mythological heroes. Beowulf has been regarded as a hero for decades, but however heroic, Beowulf embodies some monstrous tendencies. His rationale to kill repugnant monsters and gain glory in return does not work on the combat with Grendel¡¦s mother and the fire dragon, since the ogress kills Aeschere in order to avenge her only son¡¦s death; and the dragon causes strife because of the theft. The monsters, on the other hand, are somewhat heroic since they know the ethics of vengeance.