Abstract: A running machine is provided which comprises a mat member which is actuated by the tread of an exerciser so as to produce an output signal. A running circuit processes this output signal and produces a first signal when the OFF time interval of the output signal is longer than a predetermined time interval, thereby distinguishing "running" from "walking". A flying time defining circuit, included in the running circuit, defines the predetermined time interval in order to adjust the quantity of motion to be spared in the stepping and an indicating section processes the first output signal from the running circuit to indicate the number of steps.