A successful goal-achieving behavior in a design-based learning environment requires a balance between positive emotions and creative self-efficacy. However, most past studies related to the field of design education have emphasized learners’ creativity and creative performance. However, few studies have discussed avoiding motivation. To understand the influence of positive affect and creative self-efficacy on the problem-solving motivation in the context of design practice, this study explored an advertisement design course and categorized self-reported self-efficacy into confidence and ability for predicting the problem-solving motivation. Based on the mood-as-information model, which states that individuals’ positive mood influence their cognitive processes in problem solving, this study explored the levels of psychological traits and states, such as positive affect, creative self-efficacy in ability, creative self-efficacy in confidence, and problem-solving avoidance motivation in digital advertisement design. Sixty-six students majoring in advertising design at a technical high school were recruited for this study, and the average age of the participants was 17.8 years. They were asked to fill out a questionnaire after completing the project design course task. Confirmatory factor analysis was conducted on the collected data by using structural equation modeling, and a positive relationship was found between positive affect and both ability and confidence in creative self-efficacy. The two types of creative self-efficacy were negatively related to problem-solving avoidance motivation. For instance, the findings revealed that people with a high level of creative self-efficacy were less likely to face challenging problems. However, the students with a high level of motivation avoidance in terms of problem solving who had to complete a project may have less motivation to continue design improvement. By understanding these relationships appropriately, teachers can be in a better position to enhance the positive affect and the two types of creative self-efficacy of vocational high school students when they are involved in project design that can decrease their avoidance motivation to solve problems.