An oscillator includes a comparison means suitable for generating a comparison signal by comparing an internal voltage of an internal node with a reference voltage; an inverting unit suitable for inverting the comparison signal and transmitting the inverted comparison signal to an output node; a pull-up driving unit suitable for pull-up driving the internal node in response to the voltage of the output node; a discharge unit suitable for discharging the internal node; and a gate coupled between the internal node and the discharge unit, and turned on/off in response to the voltage of the output node, wherein at least part of a capacitive load included in the oscillator is electrically coupled to the internal node.