Learning part names, such as hands of a clock, can be a challenge for children because of the whole object assumption; that is, a child will assume that a given label refers to the whole object (e.g., a clock) rather than the object part (e.g., hands of a clock). We examined the effect of gaze shifting and deliberate pointing on learning part names. The experiment consisted of 2 conditions: (a) no-shifting and (b) shifting-to-object. No-shifting was when the experimenter continuously looked at the participant's face after establishing mutual gaze even while pointing at an object part to teach the part name. The shifting-to-object condition was the same as the no-shifting condition, except for the experimenter's gaze shifting to the object when teaching part names. The results showed that 4-and-a-half-year-olds and adults correctly inferred a part name only during gaze shifting. Two-and-a-half-year-olds were not yet sensitive to this ostensive flow. Especially while learning part names, a continuous gaze at the face may violate the quantity maxim--that is, the criterion that the speaker must provide the appropriate amount of information--in Grice's cooperative principle. To utilize ostensive signals in learning part names, children need to notice the combination of gaze direction and ostensive signals, such as a pointing gesture. In 4-and-a-half-year-olds, the use of social-pragmatic information is more advanced, allowing them to understand an adult's pointing gesture when gaze shifting occurs.