This paper aims at evaluating the effects and problems of the ECB monetary policy in Ireland. As far as the Eurosystem is a central bank system, the Bank has to attain two fundamental goals, that is, to stabilize the rate of increase in consumer price and to maintain the payment system in the Euro-area. However, the uniqueness of the Eurosystem makes it harder for the ECB to attain two goals for two reasons. First, a common monetary policy has different impacts on the nations in divergent business cycles. On one hand, a single Euro interest rate has a deflationary effect on the nation whose natural interest rate is supposed to be lower. One the other hand, an Euro interest rate has an inflationary effect on the nation whose business cycle is in an almost boom. Second, the present ECB's monetary strategy cannot deal with a persistent rise of asset prices. For example, in Ireland, house prices have been continuing to rise due to massive capital inflows and flexible central bank credit policy. Although heated house prices are expected to decrease in the future, the ECB cannot tighten its stance to calm down the prices. Because it is the level of consumer prices that the ECB directly targets to control, not that of assets prices. Moreover, if the house prices dropped dramatically in a short run, its drop deteriorates assets of the banks that are deeply involved in mortgage loans and real estate loons. Bankruptcy of a big bank could lead to systemic risks that damage the payment system in a nation in the Euro area. First, we look at the reasons of persistent rise of house prices and explain the role of the Ireland National Central Bank. Second, we examine the ECB's monetary strategy in terms of balancing two goals, that is, price stability and maintenance of the payment system. Third, we point out issues of the EU prudential policies.