A liquid jetting apparatus includes: a head including nozzles and driving elements arranged to correspond to the nozzles; a power source connected to the driving elements; and a control circuit connected to the power source. The control circuit determines whether an output voltage value of the power source is changed from a first voltage value to a second voltage value. When the control circuit has determined that the output voltage value is changed from the first voltage value to the second voltage value, the control circuit calculates an absolute value of a difference between the first voltage value and the second voltage value and compares the absolute value of the difference and a threshold value. When the absolute value of the difference is equal to or more than the threshold value, the control circuit determines a calculation voltage value smaller than the absolute value of the difference.