Police have raided the headquarters of Toyota Motor in Toyota City, as well as its office in Tokyo.
It comes after the arrest of senior American executive Julie Hamp on suspicion of importing a controlled substance into Japan.
Toyota President Akio Toyoda said last week that he believes she did not intend to violate the law.
It is unclear what authorities were looking for in the raid, which is common after an arrest.
Toyota spokesman Ryo Sakai told Reuters news agency that the company would not comment because an investigation is ongoing.
Ms Hamp is Toyota’s newly appointed head of public relations, the highest ranking female executive in Toyota’s history.
She was arrested on 18 June on suspicion of importing oxycodone, a narcotic pain killer, into Japan. The substance is tightly controlled in the country.
Police said the drugs were in a parcel that Ms Hamp had posted to herself.
She told police she brought the drugs into Japan to help with pain in her knees, Kyodo News reported.