Secretion signal peptides of inulinases derived from Kluyveromyces marxianus, which makes a heterologous protein produced in a yeast cell be secreted almost completely into the extracellular medium; nucleotide sequences encoding said secretion signal peptides; expression and secretion vectors comprising nucleotide sequences encoding said secretion signal peptides; recombinant yeast cells transformed with said expression and secretion vectors; and a process for producing heterologous proteins by culturing said recombinant yeast cells.