Voiced by: Miyuki Sawashiro (Japanese), Mela Lee (English), Yui Horie (early drama CD)

Shinku is the fifth Rozen Maiden doll and the first to appear in the series. Her name, in addition to its Japanese meaning, could be also a play on the Japanese pronunciation of the word "cinq" (French for "five"). She embodies the traditional Victorian aristocrat. She is extremely demanding and can seem unappreciative of others. Her favorite words are "tea", "servant" and "What?" She seems to enjoy lecturing, slapping, and generally abusing Jun, her medium, at every opportunity. She is very aware of her femininity, forever reminding others that she and the other Maidens are 'ladies'. Shinku is also perceived as being cold and angry, but she is actually very protective of, and cares deeply for, her sisters and for Jun. Shinku's presence at the Sakurada home has led to other Rozen Maidens appearing there. She hates cats because one almost swallowed her wind-up key in the past.

In the manga, Shinku is a pacifist from the beginning, saying the Alice Game must end. She doesn't like fighting her sisters, but attacks Suigintou when she is angry with her. She doesn't want any of her sisters to be lifeless, as shown when she takes Hinaichigo as her servant instead of absorbing her Rosa Mystica.

Shinku does not use honorific suffixes such as "-chan," "-san," or "-kun," except when she refers to "Father", Mitsu and once, Kun Kun. Shinku does have a cute side, which is evident in her intense, almost obsessive, admiration for the puppet detective Kun Kun, believing them to be connected by an invisible thread. In the anime, Shinku wins a human contest and receives a Kun Kun cosplay costume as her prize. Jun was once able to win her over during an argument by playing her with a Kun Kun doll.

In Rozen Maiden ouvertüre, Shinku was a lot colder and was more active in the Alice Game. She initially befriended the then broken and weak Suigintou out of pity and taught her many basic life skills, such as walking and brewing tea; However, Shinku never thought of Suigintou as a proper Rozen Maiden as the latter was incomplete; Suigintou took this remark personally later destroys Shinku's brooch out of spite, her prized possession from "Father," which opens wide the intense enmity between the two.