Fruit bearing behavior of 4 legume crops, soybean, mungbean, cowpea and lima bean, was observed under various light conditions. Response to shading varied among the species. In the 4 legumes, the dry weight of reproductive organs decreased with shading, but the declining pattern and the reproductive allocation varied with the species. In all the species, the dry weight of each sound bean remained almost constant irrespective of light conditions. Throughout the development from flower to fruit, a larger number of flower buds and immature pods underwent abortion under shade conditions than light conditions. Mungbeans and cowpeas, which bear long pods with many ovules, regulated the production of the number of sound beans by reducing the seed set in a pod as well as by reducing the fruit set. On the other hand, soybean and lima bean, which bear short pods with few ovules, responded mostly by reducing the fruit set. The regulating pattern of sound bean production by the suppressed legumes was directly related to the pod structure of the species.