Cement concrete material industry, as one of the most resource and energy intensive industries, is facing crucial social demand in the improvement of energy efficiency and reduction of carbon dioxide emission. However, little effort has been made until now to estimate the energy consumption in production processes of ready-mixed concrete plants. (abbr. RMC plants) In this paper, quantification method for electric consumption of RMC plants is proposed using easy-to-use measurement equipment. Electric consumption has been found to depend on the operation time of RMC plants as well as the production amount and concrete types. Energy-saving method without reduction of production amount or replacement of facilities is proposed using the above mentioned time-dependency.