To measure a pretilt angle in liquid crystal cells, a crystal rotation method is commonly used because of its advantages such as high precision, short measurement time and small measurement area The method, however, has the restrictions on measurable pretilt range and available cell thickness; pretilt in the range of about 16 similar to 60 degrees cannot be measured and the cell thickness should be larger than about 10 mu m. We developed a new pretilt measurement method without the restrictions of cell condition. In our new method, a pretilt angle is determined from a specific polarization direction of incident light, for which either ordinary or extraordinary wave is excited inside the cell. This method permits us to easily and accurately measure the pretilt angle in full range of 0-90 degrees.