This study carried out an investigation of professional’s scepticism as the armoured tank of an auditor. Specifically, the study aimed to; investigate the effect of auditors’ professional scepticism on fraud detection in the prepared financial statement, examine the relationship between auditors’ professional scepticism and quality of the audited financial statement and evaluate the impact of auditors’ professional scepticism on shareholders confidence in the ability of management to continue to run their businesses profitably. To achieve the objectives a survey research design was adopted to gather data for the study through the administration of questionnaire to 40 internal auditors and 10 external auditors purposefully selected and the instrument used was distributed accordingly. Both descriptive and inferential statistics of t- test were adopted for the study. The result of the study showed that auditor’s professional skepeticism had significant effect on fraud detection. It was discovered that there was a significant relationship between professional skeoeticism and quality of prepared financial statement. The result obtained further showed that auditor professional skepeticism had improved the shareholders confidence in management. The study concluded that professional skepeticism was truly the armoured tank of an auditor. It was recommended that auditors must continue to apply their professional skepeticism in order to enhance the quality of their works.