The purpose of this paper is to introduce the issue of “epistemology of ignorance, ” which has been discussed as one of the main themes of feminist epistemology, and the process of its formation, while summarizing the state of debate to date and examining how ignorance and credibility are important factors in epistemic injustice and harm. (1) we will outline feminist epistemology and review what this epistemology takes issue with. Then, (2) we will discuss why “ignorance” forms a unique problem domain for the discussion of this epistemology. Based on this, (3) we will organize several perspectives on “pernicious ignorance” as a problem for the epistemology of ignorance. Next, (4) what kind of social structure forms pernicious ignorance will be discussed in relation to credibility judgement. Finally, (5) we will organize the various injustices and harms discussed so far from the perspective of “epistemic oppression, ” and at the same time, we will discuss the points that need to be corrected that are required in response to them. The discussion of ignorance in feminist epistemology clarifies the mechanism of social structure in which ignorance arises, allowing for the condemnation of the ignorance of people in privileged positions and enabling individuals to recognize their own social position, to be aware of their epistemic responsibility based on that position, and to engage in cognitive practices that actually resist pernicious ignorance. It enables the individual to recognize his or her social position, to be aware of his or her epistemic responsibility based on it, and to actually engage in epistemic practices that resist pernicious ignorance.