The present invention provides a method for enhancing the immunogenicity using a microneedle device capable of enhancing the immunogenicity of an influenza vaccine. According to the method for enhancing the immunogenicity using the present microneedle device, a microneedle device having microneedles made of polylactic acid, coated with an influenza vaccine composed of an antigen having type A strain (H1N1), type A strain (H3N2), and type B strain as active ingredients is brought into direct contact with the skin so as to transcutaneously administer the aforementioned influenza vaccine. After the transcutaneous administration, lauryl alcohol is applied to the site of the skin where the microneedle device has been brought into direct contact.