In this study, a cutting head for a portable brush cutter was designed and for harvesting four Iranian rice varieties, two varieties of high yielding named Khazar and Fajr and two varieties from local varieties named Binam and Hashemi. Cutting head consisted of a circular saw blade with 24 cm diameter and 2 mm thickness. Designed blade had 136 teeth with 0° rake angle, 30° clearance angle and 6 mm pitch. A simple windrowing system made from aluminum sheet was designed and constructed. The cutting head installed on existent brush cutter and test was conducted in field conditions. For each type of variety, the cutting energy and critical blade speed was computed. Results indicated that compared to local rice varieties Maximum power consumption of about 1.132 kW was obtained for Khazar variety. Results also showed that rice losses of the portable reaper were lower than manual harvesting and field capacity of machine was 4.20 times greater than manual harvesting