Over the last 15 years of the XXI century the RF government has significantly increased the volume of investments in the public sector of economy, which enabled the formation of the unprecedented number of unique infrastructure projects.At the same time the Russian economy, if we consider its public and private sectors as parts of the unitary whole, has not succeeded in responding to these government's initiatives with corresponding changes that, for instance, could have been supported with higher indicators of its competitiveness. The article focuses on the factors influencing volume, structure, and dynamics of investments in the public sector of economy, as well as conditions for an effective mobilization and usage of investment resources in the public sector of economy. In respect to the economy of the Russian Federation causes of low investment attraction of the public sector are analyzed. The experience of world economy development shows that besides qualified personnel on the part of all the participants of the investment process, minimal necessary conditions of effective mobilization and usage of investment resources in the public sector of economy are as follows: the access on the part of the state, society and potential investors to complete and reliable information on the composition, production characteristics and quality of economic and social infrastructure in the country; the existence of legal certainty in the legislation regulating investment and other economic activities as well as confidence of investors in the state's legal system ensuring the adherence of the state to its own rules; the existence of a developed civil society; the availability of sufficient number of competitive suppliers and contractors specializing in the production of capital goods (works, services); the presence of state's own structures having successful experience in standardizing of challenging project management processes. At present the RF economy is in the state of deep institutional imbalance and consequently its separate subjects, whose practice of economic analysis could be effectively reproduced within the boundaries of the whole economic system, do not have real support either from the state or from the society. Through the example of а public-private partnership institute, it is shown how the shortage of certainty on the way of Russia's mastering of modern economic mechanisms holds the efficiency of investments in the public sector of economy.