A converter controlling device for a hybrid vehicle and a converter controlling method for a hybrid vehicle. A monitor monitors a state of charge (SoC) of a low voltage battery, a SoC of a high voltage battery, and a load value of an electronic load. A comparator compares a level of the SoC of the low voltage battery, a level of the SoC of the high voltage battery, and the load value of the electronic load with a first charging threshold value, a second charging threshold value, and a load threshold value. A determiner determines whether to adjust an output control value of a converter. A control value adjuster decreases the output control value of the converter to be lower than a level during normal control or increases the output control value of the converter to be higher than the level during the normal control.