The aim of this study was to provide the behavioral data demonstrating the emotion/valence nodes which were activated by facial expressions. This was attempted by investigating the priming effects based on the same facial expression of two successively presented different persons. In the experiment, two faces of the same or different person with smile or neutral expression were sequentially presented on the right or left side of fixation. Fifteen participants judged the location or the facial expression of the first (prime) and second (target) faces respectively. A combination of prime-target person identity (same, different), expressions (smile/smile, smile/neutral, neutral/smile, neutral/neutral), and tasks (location/location, location/expression, expression/location, expression/expression) made 32 different conditions. Results showed that when participants judged location of a prime and facial expression of a target, reaction times to target were shorter for smile face repetition than other combinations of face expression regardless of the identity of person. This priming effect was not observed when neutral faces were repeated. The results suggested that a smile face activated a happy/positive node in the associative network, and this facilitated the processing of subsequent happy expression face.