The index signal generator generates an original signal every the rotor of the direct-drive motor rotates, and delays the original signal by a delay time to produce index signal. The index signal generator comprises, as the delay giving the delay time, the delay counter that can be set the initial value, instead of an analog delay circuit, a variable register and a capacitor. The delay counter comprises the counter and the counter value selector for determining the initial value of the counter. The counter starts to count the clock signals generated by the clock in response to the original signal, and stops counting the clock signals and generates the index signal when the number of the clock signals counted by the counter reaches the initial value.