PURPOSE: To make it possible to easily know shift timing to an optimum gear position, by turning an indicator lamp on and off by a shift-up and a shift-down oscillation signals of an oscillation circuit.

CONSTITUTION: When a clutch is connected and an accelerator is pressed while a gear position is at a second speed, switches SW5, SW6 are offed and an indicator lamp L2 is turned on and off. When the rotary number of an engine reaches 4,000rpm, the output of a comparator Comp1 is one and the output of a comparator Comp2 is zero. Because all input terminals of an oscillator 10 come to one, oscillation output is displayed from the terminal 1 and the output of an AND gate Q4 is oscillated while a transistor Tr3 is turned on and off corresponding to an oscillation cycle to turn the indicator lamp L3 on and off and indication such that shift up is performed and a gear position instructing to a third speed position is imparted to a driver.