A translational control method using an RNA-protein interaction motif is provided. The method comprises a step of introducing an mRNA having: a 5′UTR regulation structure comprising: (1) a cap structure at the 5′ terminus, (2) a spacer positioned on the 3′ side of the cap structure, and (3) one or more RNA motifs positioned on the 3′ side of the spacer, which comprises an RNA-protein interaction motif-derived nucleotide sequence or a variant thereof; and a nucleotide sequence encoding a target protein gene on the 3′ side of the 5′UTR regulation structure, into a cell in the presence of a protein specifically binding to the RNA motifs, wherein a translational level is decreased as the number of bases of the spacer decreases, and the translational level is decreased as the number of the RNA motifs increases.