Using a nucleic acid construct, association of a polypeptide with a sequence coding therefor and screening of a polypeptide that binds to a target substance are carried out, which nucleic acid construct comprises a 5′-untranslated region and a coding region, wherein the above-mentioned coding region comprises a sequence coding for a polypeptide subjected to be displayed, a sequence coding for a first nucleic acid binding polypeptide, and a sequence coding for a second nucleic acid binding polypeptide； the above-mentioned 5′-untranslated region comprises a first sequence capable of binding to a first nucleic acid binding polypeptide and a second sequence capable of binding to second nucleic acid binding polypeptide； and, when the above-mentioned nucleic acid construct is introduced in a translation system, a fusion protein translated from the coding region of the above-mentioned nucleic acid construct forms a complex with an RNA corresponding to the above-mentioned nucleic acid construct.
