Among the 15 justices of the top court's Grand Bench, 14 ruled the 2021 Lower House election was constitutional, while one said it was unconstitutional.
A magazine said that Minoru Terada "falsely reported" that he covered some gasoline and other expenses related to last year's Lower House election, which were paid by a support group.
Kihara, a member of the lower chamber of parliament, is the closest aide to Prime Minister Fumio Kishida, also president of the ruling Liberal Democratic Party.