Preheat oven to 375°. Grease 9 x 5-inch loaf pan with margarine.
Sift millet flour, baking powder and baking soda into medium bowl. In another medium bowl, cream margarine and sugar until light and fluffy. Beat in eggs, 1 at a time. Add dry ingredients to creamed mixture alternately with bananas.
Pour batter into greased pan. Bake in preheated oven until wooden pick inserted into center comes out clean, about 1 hour. Let cool in pan 10 minutes. Remove from pan. Place on wire rack to cool.