The 39-year-old, who wrote "Shimotsuma Monogatari" (Kamikaze Girls), was charged with violating the Cannabis Control Law after being stopped in the Kabukicho district, Mainichi Daily News reported Monday.
When questioned by police, he reportedly admitted having used the drug.
Investigators said Takemoto was walking home Sunday evening when he was stopped and questioned by an officer. He admitted to having the drug.
The Japanese author is popular among young women for his "Soreinu" essays in the Osaka subculture magazine "Hanagata Bunka Tsushin."
His writings, "Emily" and "Lolita," were nominated for the Yukio Mishima Literary Prize.