This character dresses in the Lolita style.

Lolita is a fashion subculture originating in Japan that is based on Victorian-era clothing as well as costumes from the Rococo period, but the style has expanded greatly beyond these two.
The original silhouette is of a knee length skirt or dress with a 'cupcake' shape assisted by petticoats, but has expanded into various types of garments including corsets and floor lengths skirts. Blouses, knee high socks or stockings and headdresses are also worn.

Lolita fashion has evolved into several different sub styles and has a subculture that is present in many parts of the world.