The present invention relates to a process for secretory production of a foreign protein, in particular, transglutaminase by a coryneform bacterium.According to the present invention, a process is provided for the secretory production of a foreign protein, in particular, transglutaminase, by making a coryneform bacterium to produce an industrially useful foreign protein, in particular, transglutaminase and efficiently release the product extracellularly (i.e., secretory production).An intended foreign protein, in particular, transglutaminase, is produced by using an expression construct wherein the gene sequence of the intended foreign protein containing the pro-structure part, in particular, pro-transglutaminase gene sequence, is ligated to the downstream of a sequence encoding the signal peptide region from a coryneform bacterium, introducing this expressional genetic construct into a coryneform bacterium, culturing the thus transformed coryneform bacterium, and treating the extracellularly released protein with a protease, etc. to cleave and eliminate the pro-part.