This paper discribes an analysis for the sleeve monopole antenna with single sleeve. The structure of the proposed antenna is very simple. Therefore, it is very economical in terms of manufacturing and installation which makes it convenient for either portable or mobile use by making an up-and-down type antenna. In the method of analysis, instead of the complex electro- magneticapproach, we used a lumped element equivalent circuit derived from the information about the electrical dimensions and the resonance characteristics of the antenna. An error between a resonant frequency by lumped-element circuit analysis of the proposed antenna and a measured one by an experiment is below 0.9%. It is shown that the theoretical and experiment results are little different.