To effectively produce apple with red coloration and marked eating quality, we investigated the efficacy of a chemical defoliant. The manual removal of leaves covering fruit to improve coloration is a labor-intensive process, and a defoliant consisting of fenitrothion is expected to be a substitute for this process. Leaves fell heavily on treatment with the defoliant, with an increase in the average maximum temperature for three days from days one to three after the treatment, and the optimum efficiency of defoliation was obtained when the average maximum temperature for three days was 27°C. The optimal time point to apply the defoliant to ‘Fuji’ was two months before harvest, being one month earlier than the standard time point for Morioka. When leaves covering fruit were removed two months before harvest, the soluble solid concentration of the fruit in trees with a low leaf-fruit ratio was lower than in trees with a high leaf-fruit ratio. The water core of ‘Fuji’ was not reduced by leaf removal at two months before harvest in the case of a high leaf-fruit ratio, whereas it was reduced by leaf removal at one month before harvest in the case of a low leaf-fruit ratio. The fruit eating quality was not influenced by leaf removal at two months before harvest when 60 leaves per fruit were maintained on the trees. Therefore, when leaves are removed by a defoliant two months before harvest, the crop load of the trees should be controlled to maintain 60 leaves per fruit. Since the improvement of fruit coloration raised the price rating, the profit per day was estimated to increase, although the number of fruit on the trees was reduced to maintain a high leaf-fruit ratio. The time required for manual leaf removal was estimated to be reduced by 60% using the defoliant.