In a projection system, providing a stop that forms an opening that is symmetric with respect to a first flat plane including the projection system optical axis and a first axis that extends in parallel to the first direction and intersects the projection system optical axis but asymmetric with respect to a second flat surface including the projection system optical axis and a second axis that extends in parallel to the second direction and intersects the projection system optical axis allows appropriate light adjustment at the stop even when pencils of light from the points in a video device exit at different angles along a second direction, whereby high-quality video images can be provided with the size of an optical system further reduced and therefore the size of an overall virtual image display apparatus reduced.