A driving apparatus of a linear motor which reciprocally drives a movable element
supported by an elastic member, includes an inverter that converts a direct current
power into an alternating-current power with a specified frequency to drive the
linear motor, a current detector that detects the output current of the inverter,
a voltage detector that detects the output voltage of the inverter, an amplitude
detector that detects an amplitude of the movable element of the linear motor,
an amplitude controller adjusts the output current or output voltage in a first
control cycle so that the amplitude of the movable element is a desired constant
value, and a resonant controller that adjusts the output frequency of the inverter
in a second control cycle which is larger than the first control cycle so that
the output current of the inverter is substantially minimum on condition that the
amplitude is substantially constant.