Reading books is a fundamental cornerstone in the formation of young minds, and it influences various facets of children's lives. Recent technological advances have led to extensive research into the potential role of robots as companions in children's reading experiences. This study explores how to engage children in reading through human-robot interaction, deriving three design specifications: a robot with an animal-like appearance; a robot that responds as a real organism; and a robot that reacts based on reading status. An interactive reading companion robot named Book-Toki was developed, which has the appearance of a rabbit. The robot's ears, made of deformable silicone, and the robot's head move in response to the child's reading. As the child reads the book aloud, the ears change shape from folded to unfolded, and the head slowly peeks out of the burrow, symbolizing active concentration. This visual response sparks children's imagination and gives them a sense of 'I am listening to you,’ which enriches the reading experience. In this way, robots can play a significant role in making reading a more enjoyable experience for children.