This study aims to explore pre-service biology teachers' value orientation in terms of scientific observation and representation in plant cell microscope observation experiment. This study focuses on the pre-service teachers' value orientation in relation to objectivity. To achieve this aim, we used a hypothetical situation that pre-service teachers should teach tacit knowledge related to observation and representation during the cell observation class. We presented a hypothetical situation to fifty pre-service biology teachers and collected their answer about that hypothetical situation. These answers were categorized inductively based on constant comparative analysis. The result shows that four types of pre-service teachers' value orientation, 'presence confirmation', 'mechanical objectivity', 'students' subjectivity', and 'trained judgement', are confirmed. This result also shows that various value orientation could be reflected on teaching an experiment and tacit knowledge related to the experiment. Also, many pre-service teachers value 'mechanical objectivity' in observation and image representation. Also, pre-service teachers' value orientation and perception of objectivity in scientific practice could have an influence in teaching science, this result could give provide suggestions on science teachers' education in terms of scientific practice.