PURPOSE: To exactly indicate time for transacting stocks by reading a variable rate P and a variable rate Q concerning an equal period or a shorter period from a storing means and displaying the change in the period in the form of a graph having scales common for the both.

CONSTITUTION: This device is composed of a timer 1, week final price storage circuit 2, 13 weeks final price average calculator 3, 26 weeks final price average calculator 4, dividers 5 and 6, subtracters 7 and 8, storage circuits 9 and 10 and display 11. A stock price index such as the average stock price in 500 types in Nikkei is worked to generate a variable rate P and a variable rate Q, and the fluctuation in these P and Q is expressed by the graph. In this case, when the variable rate P goes through the variable rate Q from down to up, it is time for buying and reversely when the variable rate Q falls down and the variable rate P goes through the variable rate Q from up to down, it is time for selling. Thus, the time for buying and selling the stocks can be exactly recognized.