Canon refers to information that is considered "official" by a fictional universe's fan-base. In this case the word canon refers to information that is considered official for Detective Conan.
In Detective Conan only the information, storylines, settings, and characters found in the manga and information given by Gosho Aoyama in interviews are considered to be canon.
Canonicity is relevant in the fandom because non-canon material can impact the reader's ability to solve the story's mysteries or logically contradict the main storyline. Alterations or omissions in the anime have introduced serious plotholes that create logical inconsistencies or remove clues so that cases are harder or impossible to solve. Because of this, even manga-based episodes are generally considered suspect and the manga overrides the anime in canonicity where the two conflict.
The following sources of information are considered to be non-canon and are deemed unofficial:
- Detective Conan Special
- TV original episodes
- Video games
- Drama specials and series
- Modifications made by foreign adaptations of Detective Conan, such as name changes
- Any change in the TV episodes that makes them different from the original manga, including additional anime-original scenes, dialogues, and information
 Non-canon information that has become canon
Certain elements from non-canon sources have been turned into canon via Gosho Aoyama and the manga series.
 Wataru Takagi
Wataru Takagi was first introduced in On Location, TV Drama Murder Case as an unnamed police detective that had accompanied Inspector Megure on the scene. For some time, this character only appeared in the TV original episodes directed by Haruo Ogawara. The character's name is first given as "Detective Takagi" in the credits for the Karaoke Box Murder Case despite his face not actually appearing on-screen. Although the Karaoke Box Murder Case was based on a manga story, Takagi does not appear in the original. Takagi receives his first manga canon appearance in the Actor's Apartment Case.
 Ninzaburo Shiratori
 Detective Chiba
Detective Chiba was first introduced in the anime version of The Final Screening Murder Case and received his first canon manga appearance in Sato's Father Case. Curiously enough Chiba's first name has not been given in the manga or anime. Aoyama has implied in an interview that since Wataru Takagi was named after his voice actor it was unlikely he would repeat himself by giving Detective Chiba his voice actor's first name (Isshin) too.
 Azusa Enomoto
Azusa Enomoto was first introduced in The Mysterious Old Man Disappearance Case as a waitress at Café Poirot as a background character. She receives her name and first speaking appearance in The Deduction That Was Too Good. Her first canon manga appearance occurs during the Forgotten Cellphone Case.
 Midori Kuriyama
- Misao Yamamura was first promoted to inspector in The Raven Chaser, and this was referenced in the anime in The Witch Enshrouded by Fog, and then made it to the manga in the Kappa Murder Case.
- The telescopic lens modification for Conan's glasses that was introduced in Countdown to Heaven has entered manga canon in the Unsmashable Snowman Case.
- ^ Interview gab Gosho Aoyama am 22. Juli 2006 im Rahmen einer Pressekonferenz auf dem Comic-Salon in Erlangen
Interview with Gosho Aoyama on 22nd July 2006 at a press conference at Comic-Salon in Erlangen
Q: In einem der Kinofilme legt sich Sonoko eine andere Frisur zu(siehe Film 5). Wird sie diese Frisur auch in Manga bekommen?
Q: During one of the movies Sonoko got a different hairstyle (see movie 5). Is she also going to get this hairstyle in the manga version?
A: Die Filme und die Manga sind völlig getrennt. Im Manga wird Sonoko also ihre alte Frisur behalten.
A: The movies and the manga version are completely separated from each other. So Sonoko will keep her old hairstyle in the manga version.
transcript in German
translation credit to Aki-kun
- ^ "Translating Interviews". justwantanaccount. 2012-01-12. http://www.detectiveconanworld.com/forum/topic/1555-translating-interviews/page__view__findpost__p__245256. Retrieved on 2012-04-29.