Environment-friendly “green” composites were fabricated from a starch-based, dispersion-type biodegradable resin and cellulose nanofibers. The mixture of the dispersion-type biodegradable resin and cellulose nanofibers were blended well by using a home-use mixer and a stirrer, and then dried in air or in a vacuum. Composites were prepared by conventional hot pressing at a constant temperature of 140°C and at pressures from 10 to 50 MPa. Their flexural strength as well as flexural modulus increased with increasing the molding pressure, and were also affected by preparation methods and conditions. Their mechanical properties such as strength and modulus had a good correlation with their density. Especially it can be seen that there is significant effectiveness in a stirrer mixing process, which results in the improved uniform dispersion of nanofibers.