The firm said it had been "fully cooperating" in a European Commission probe on compressors, which are used to cool refrigerators and freezers, that Panasonic and other manufacturers sold on the continent.
On Wednesday, the Commission said it had fined the firm and three others -- Italy's ACC, Denmark's Danfoss and Brazilian firm Embraco -- a total of 161.2 million euros for running a price-fixing cartel from April 2004 until October 2007.
Panasonic's participation began in November 2006, it said, adding that a fifth company, US-based Tecumseh, acted as a whistleblower and was not fined.
"Panasonic is carefully assessing the Commission's decision," the company said in a statement Thursday, saying it took "this matter seriously and will make every effort to maintain the public's confidence."
"It is the policy of Panasonic to comply with all applicable laws and regulations, including anti-trust regulations," it added.
Panasonic shares closed 2.85 per cent lower at 714 yen.
"The impact of the news appears minimal, and the amount of the fine is not too significant," Kenichi Hirano, operating officer at Tachibana Securities, told Dow Jones Newswires.
Panasonic said the fine would have no material impact on its financial forecast for the fiscal year ending in March.
Last month, ratings agency Standard & Poor's downgraded Panasonic's credit rating, after the company said it expected a loss of $5.4 billion this year as a strong yen and one-off charges reversed previous expectations for a profit.
In October 2010, Panasonic said it had agreed to pay $49.1 million in fines as part of a plea agreement with the US Department of Justice in a separate price-fixing case involving refrigerator compressors.
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