This study examines the effect of shared book reading on mother-infant joint attention interactions in infancy. In experiment 1, pairs composed of 9-month-old infants and their mothers (N = 10) were observed in three conditions: the shared-book, toy-play, and no-material condition. The results indicate a frequency of passive joint and coordinated joint attention in the shared book context than in others. Experiment 2 longitudinally investigated the effect of increasing the time of shared book reading on the frequency of passive and coordinated joint attention. Twenty-eight pairs of 9-month-old infants and their mothers were randomly assigned to one of two groups; the first was a shared book reading condition (N = 11), in which mothers were asked to share books every day and were given picture books regularly from the first observation (at 9 months) until the second observation (at 12 months). In the control group (N = 11), mothers were given no instruction. The results show that increasing shared book reading increases the frequency of passive joint attention. Therefore, it is suggested that shared book reading increases joint attention episodes and that repeated shared book reading increases it in other contexts.