The structure of a scale of generativity was examined and gender differences were investigated among 649 men and women in their forties and fifties in Japan. Results indicated that generativity consists of two factors: generative consciousness and the will to make social contributions. Gender difference was seen in both factors: men had higher generative consciousness while women had higher will to make social contributions. These results suggested that the difference in the social share due to gender influenced the state of generativity among middle-aged people in Japan.