Keywords: perfect competition, monopolistic competition, oligopoly, monopoly Introduction Monopoly occurs when there is no competition and then the supplier has a very high amount of pricing power. In addition, monopoly also is a situation in which a single organization or group possesses all or nearly all of the market for a given type of product or service. Besides, it also includes several characteristic, example and diagram in monopoly market. In addition, there are four common types in competition free market which is ideal competition, monopolistic competition, oligopoly and monopoly. There will vary interpretation, features and illustrations in these four common types in market. Monopoly A monopoly is when there are many potential buyers but there is merely one seller that regulates the way to obtain a product and its price.