The first episode of the British series Dragon's Den was titled “Episode 1.”
The opening instalment introduced the British audience to the programme's pitch structure, in which entrepreneurs entered the Den seeking investment from a panel of businesspeople. It formed part of the first series that began broadcasting on BBC Two in January 2005.
Unlike some television programmes, the early Dragon's Den episode listings used straightforward numbered titles rather than distinctive descriptive names. That makes the canonical answer shorter than many viewers expect. Episode titles can also vary in databases that use broadcast descriptions, production labels, or episode numbers.
This question refers to the British series and its first listed instalment, not the opening episode of an international version such as the Canadian Dragons' Den or the American Shark Tank. Those programmes have different episode-title conventions and transmission histories.