An alternative to animals, which bring various benefits to people but are not always easy to own, is pet robots, whose central role is to communicate with people. However, there is insufficient research on how pet robots should behave to evoke feelings of affection in people. We focused on blinking as one of the behaviors of the eye and investigated what type of pet robot blinking pattern evokes more feelings of affection in people. First, we designed seven different blink patterns combining short and long blinks through a pilot study. We then conducted a study with 15 participants to compare the patterns using a paired comparison method. The results showed that the blink patterns that were more likely to evoke affection were those with consecutive short eye closures (three times rather than two), whereas the blink patterns that were less likely to evoke affection were those with several long eye closures.