An 8-year-old boy. He was originally the high school detective Shinichi Kudo, but he shrunk after being forced to take a poison called APTX4869. He hides his identity because if it were revealed, not only his life but also the lives of those around him would be in danger. Living with Ran at the Mouri Detective Agency, he uses a stun-gun wristwatch to put Kogoro to sleep and uses a voice-changing bowtie invented by Professor Agasa to solve cases in Kogoro's place. He possesses an incredibly high IQ of 400. The people who know his true identity are Heiji, Professor Agasa, and Ai. He is close with Guest. He knows that Ai also took APTX4869 and shrunk, and he keeps this fact a secret from others. He is a member of the Junior Detective League.

Kogoro's daughter and a high school student. She is in love with Shinichi and misses him deeply since he disappeared. She lives at the Mouri Detective Agency and cares for Conan. She is close with Guest. She is extremely skilled at Taekwondo and is a formidable fighter. She has a very kind personality.

Ran's father and the head of the Mouri Detective Agency. He treats Conan like a mere brat. He always comes up with ridiculous deductions, but because he is put to sleep by Conan's stun-gun, he is famously known as "Sleeping Kogoro." Of course, he doesn't actually solve the cases; Conan does the work while he is unconscious.

A brave character who dives headfirst into any situation. He is one of the few people who knows Conan is actually Shinichi, and he helps keep that secret. He possesses bold initiative and strong mental fortitude. Like Conan, he is a brilliant detective. He is a high school detective and a young man.

A member of the Public Security Bureau of the National Police Agency. He works part-time at a cafe to maintain his cover. While he is polite and friendly to everyone on the surface, he has a sharp and rational inner personality. He is close with Conan. He is a highly intelligent man.

An 8-year-old girl. Like Conan, she took APTX4869 and shrunk. She knows Conan's identity as Shinichi but keeps it hidden (Conan is aware that she knows). She is highly intelligent and acts as Conan's friend and assistant. She is a member of the Junior Detective League.

A member of the Junior Detective League along with Conan. He is a complete man of action. He often causes trouble for Conan.

A girl who is a member of the Junior Detective League. She has a crush on Conan. She has a very gentle personality and cries easily. She often causes trouble for Conan.

A knowledgeable and logical young boy. He is a member of the Junior Detective League.

An inventor who creates the gadgets Conan needs for his investigations, such as the solar-powered skateboard, voice-changing bowtie, and stun-gun wristwatch. His experiments often end in failure. He has a kind and warm personality. He is one of the characters who knows Conan is Shinichi and helps keep the secret (Conan is aware that he knows). He is a 53-year-old man.