The purpose of this paper is to test empirically economies of scale, defined by technologyin Intra-Industry Trade(IIT). B.Balassa found first the existence of IIT. Grubeland Lloyd, Linder, Dreze, and others treated IIT as consisting of final goods.But P.Raymentfound that IIT consists mostly of intermediate goods and he tried to explain IIT byeconomies of scale and specialization. However, to test the relationship between economiesof scale and IIT, I will use I.Ozaki's definition on economies of scale, defined by technology.I.Ozaki sees technology, measured in plant scale, as the basis of economies ofscale. In order to connect the relation between the economies of scale and IIT, Ozaki'stechnology types, classified by statistically estimated parameters values must be firstintroduced. I converted this into Standard International Trade Classification (SITC) data,then calculated Balassa index for each of these sectors and see if economies of scale andIIT can be related. Through this empirical test,I confirmed the assumption that IIT isbased on economies of scale, defined by technology. Also, I found that this relation didnot exist in East-West trade.The outline of my paper is as follows:First, representative theories and measurementsof IIT of industrial countries are shown. Second, considering that IIT is made up mostlyof intermediate goods, Rayment, trying to explain IIT by specialization and economies ofscale, will be introduced. In order to empirically test this relationship, I introduceOzaki's definition on economies of scale, based on technology. Third, empirical results, using Ozaki's technology types, on IIT with eocnomies of scale and specialization isstated. France, Germany, EC, Austria, and Hungary are taken as example. Fourth, explanationof the whole process is summarized and last but very important, further research is mentioned.As a further research, an empirical analysis of IIT, explained by the economies ofscale and specialization,has to be pursued. I will provide an example by analyzing theautomobile's components within EC countries and between eastern and western countries. Iwill follow my analysis by taking General Motors(GM) in Europe as an example and try tosee GM's export and import of components of automobiles to and from Austria, Countrieswhich I will be handling with are:Austrian trade with Germany, France, United Kingdom, Spain,Belgium and finally to see East-West trade, Hungary-Austria will be taken as an example.