Disclosed is a power transmission controller for an electronic calculator which controls power transmission to a computation circuit and a display device included within the electronic calculator. The power transmission controller indicates a forthcoming termination of the power transmission at a first stage in unison with a first control signal derived from a timer circuit through said display device. Then the power transmission controller terminates said power transmission at the second stage in accordance with a second control signal derived from the timer circuit. A clear key for conducting a clear operation functions to initiate the power transmission to said computation circuit and said display device.