The present invention relates to an antihypertensive agent including a boysenberry seed extract as an active ingredient. According to the invention, there can be provided an effective and highly safe antihypertensive agent having antihypertensive effect so that the agent can contribute to the prevention and amelioration of hypertension and having very little risk of side effects even in continuous intake, and a method for producing the antihypertensive agent at low cost and efficiently.
