A rear-projection type display device has a projection device, a transmission type screen, a housing, and input means. The projection device projects a light from a light source, as an optical image. The optical image is projected to the transmission type screen. The housing accommodates the projection device and the transmission type screen. A user operation is inputted to the input means. The rear-projection type display device includes a storage section, a distortion amount detection section, a correction amount calculation section, and a correction section. The storage section stores a distortion detection image to be displayed on the transmission type screen. The distortion amount detection section changes the distortion detection image in accordance with an operation inputted from the input means, and detects a distortion amount of the image based on operations inputted by the input means until the distortion detection image displayed on the transmission type screen is brought into a predetermined state. The correction amount calculation section calculates a correction amount based on the distortion amount. The correction section corrects an image projected by the projection device, based on the calculated correction amount.