Current treatment for process addiction, such as gambling disorder and game addiction, is primarily psychotherapy, and effective pharmacotherapy has not been established. One reason is the lack of appropriate behavioral test batteries for mice to identify the causes of addiction and conduct pharmacological tests. The scarcity of high-value rewards is generally considered the cause of addiction, and experimental behavioral tasks have been proposed accordingly. In recent years, however, it has become clear that signs that foretell rewards are involved in the formation of gambling addiction. In the present study, we developed a 2-hole nose poke-selective operant task for mice in which two retractable levers were used as predictive signs for the reward. As a result, mice showed adherence to the option with predictable rather than unpredictable reward signs. Adherence to the predictable reward signs continued even after the reward probability decreased. We also found that the suboptimal behavior formation was correlated with the frequency of sign tracking. This study allows us to study the role of sign tracking in the shape of process addiction using genetically engineered mice and drug administration models.