1. An exposure condition determining method with which to determine exposure conditions for transferring a pattern arranged on a first plane onto an object arranged on a second plane via a projection optical system, said method comprising: transferring a test exposure pattern including a predetermined measurement pattern and a reference pattern sequentially onto a plurality of part areas on said object via said projection optical system while changing at least one of exposure conditions under consideration, said reference pattern being formed on said object having a photosensitive layer on its surface to be thicker in line width than said measurement pattern; picking up an image of said plurality of part areas on said object on each of which said test exposure pattern has been transferred under the exposure conditions of different values and performing pattern-matching with predetermined template pattern data on the image datum of each part area, said template pattern data including image data corresponding to said reference pattern; and determining said at least one exposure condition under consideration based on results of said pattern-matching for said part areas.