The inverter according to the invention includes a control microcomputer including a protector circuit that stops the inverter when an anomaly is caused, a counter that counts the driving clock signals of the microcomputer from the instance at which the protector circuit starts working, and a conversion circuit that converts the clock signals counted by the counter to a numerical time expression in the time units and outputs the converted numerical time expression. The inverter according to the invention, manufacturable with low manufacturing costs and easy to operate, facilitates informing the installation manager of the period of time from the instance at which the inverter stopped due to an anomaly and such a cause, without impairing the time measurement precision.