We investigated the gain-loss effect of virtual/personal assistant character, which provides intelligent assistance to humans, and focused on not only the first impression of using the assistance but also changing impression about the character when used multiple times for assistance. The experiment used a fictive retrieval system (searching onomatopoeia), and the virtual assistant character looked up for suitable words for the user (success), or failed to find the words (mistake). There were three sessions, differing by the task of character’s mistake; two tasks were successes and one was a failure in each session. The results showed that the group of people who had low expectation from its first appearance, formed negative impressions after the final mistake, significantly. Consequently, final mistake influenced the formation of negative impression more than other mistakes, thus showing that the final mistake in multiple times of assistance was associated with loss effect.