This study is carried out to evaluate the actual relationship between the three hole areas (9.62, 15.90 and 23.76 mm²) and the feeding device parameters (seeding speed, peripheral speed of metering wheel device. The hole of feeding device was controlled by seed lever control which lies in seed tank bottom. All parameters were measured at constant level of seed brush parameters. Quality of feed, miss, multiple indexes and preciseness of seed index are the most common characteristics used to evaluate the metering wheel device performance. Varies physical properties of seeds including seeds density, projected area, sphericity and one thousand seeds mass are the most important factors in determining the optimum levers dimensions for metering device. The highest seed feed index was achieved on the seed plate with oblong holes (A_ob2) for all cowpea moisture content (M₁ of 64.45%; M₂ of 56.13% and M₃ of 49.74%), and the plates with circular holes followed this. The lowest seeding feeding ratio was obtained from the experiments using the plates with oblong hole (A_ob1). The highest seed feed index was with moisture content (M₁=86.08%) at 1.0 km/h, whereas the lowest the seed feed index was with M3 (46.21%) at 4.0 km/h. When the seed feed index was 86.73%, 79.77% and 74.56% for M1, M2 and M3 cowpea moisture content at 1.0 km/h planting speed, the seed feed index reached 71.04%, 61.07% and 46.21%, respectively, in a planting speed of 4.0 km/h. The changing planting speed had a greater effect on the feed index of M3 cowpea seed on the other 2 seed moisture content.