1. A 2-dimensional pattern matching method comprising: previously enrolling an enrollment 5 feature data which is a vector data in a feature space; inputting a query 2-dimensional pattern; extracting a query feature data by projecting a vector representation of either of said query 2-dimensional pattern and a transformed query 2-dimensional pattern which is generated by transforming said query 2-dimensional pattern into the feature space; generating a enrollment 2-dimensional pattern and a reconstructed query 2-dimensional pattern by inversely projecting said enrollment feature data and said query feature data into a 2-dimensional pattern representation space which has dimensions of the vector representation; and calculating a similarity between said enrollment 2-dimensional pattern and said reconstructed query 2-dimensional pattern.