We examined whether Japanese people, 47 junior high school students, 49 undergraduates, and 52 older adults, possessed negative attitudes against blacks and the picture book Little Black Sambo. We assessed the implicit attitude toward the target word pairs, “black/white” and “Sambo/Heidi,” by utilizing a paper-based Implicit Association Test and found that both black and Sambo were associated more negatively than white and Heidi. However, the implicit attitudes assessed with a single-target IAT showed that 67 Japanese students showed positive implicit scores for blacks but with smaller valences. A post hoc analysis revealed that the reading experience of Little Black Sambo did not show a significant difference between the implicit attitudes of those who had and had not read the book.