We report a case of panic disorder treated with keishikyokeikabukuryobyakujutsuto. The patient was a 42-year-old woman who had one or two episodes of panic attacks every month for 1 year accompanied by dyspnea, fear, rigidity of hands, etc. The episodes were more frequent with physical exertion and menstruation and did not improve with kamishoyosan or kanbakutaisoto. Then, after a car accident, she had a panic attack with a stronger intensity. Blood and imaging examinations revealed no special findings, and we diagnosed her with panic disorder. We considered her complaint as Honton disease and administered ryokeikansoto. After 2 weeks, her mental condition improved, and dyspnea and fear of attacks relieved. After 2 months, office work became more strenuous, and attacks recurred once or twice a week. An abnormal sensation of the posterior cervix occurred as a prodrome of an attack, and simultaneously, she noticed neck stiffness. After switching to keishikyokeikabukuryobyakujutsuto, the cervical sensation disappeared, neck pain and neck stiffness were relieved, and the attacks did not reappear. This case suggested that keishikyokeikabukuryobyakujutsuto was useful for the prevention of panic attacks associated with neck stiffness.