An insulation resistance measurement apparatus comprising: a first resistance unit having a first end connected to a positive electrode of a battery and a second end connected to a ground, wherein the first resistance unit is variably controllable between having a first resistance value or a second resistance value greater than the first resistance value; a second resistance unit having a first end connected to a negative electrode of the battery and a second end connected to the ground, wherein the second resistance unit is variably controllable between having a third resistance value or a fourth resistance value greater than the third resistance value; a voltage measurement unit configured to measure a voltage across the first resistance unit and a voltage across the second resistance unit; and an insulation resistance calculation unit configured to calculate a first insulation resistance value between the positive electrode of the battery and the ground and a second insulation resistance value between the negative electrode of the battery and the ground based on the first resistance value, the second resistance value, the third resistance value, the fourth resistance value and the voltage measured by the voltage measurement unit, wherein the first resistance unit includes a first resistance value unit that is ON/OFF controlled by a first switch and a second resistance value unit (R1, R2) that is ON/OFF controlled by a second switch, wherein the first and second resistance value units (R1, R2) are connected in parallel between the positive electrode of the battery and the ground, wherein the second resistance unit includes a third resistance value unit that is ON/OFF controlled by a third switch and a fourth resistance value unit that is ON/OFF controlled by a fourth switch, wherein the third and fourth resistance value units (R1, R2) are connected in parallel between the negative electrode of the battery and the ground, and characterized in that when the first switch or the second switch of the first resistance unit is ON, the insulation resistance calculation unit controls the third switch and the fourth switch of the second resistance unit to be OFF. a first resistance unit having a first end connected to a positive electrode of a battery and a second end connected to a ground, wherein the first resistance unit is variably controllable between having a first resistance value or a second resistance value greater than the first resistance value; a second resistance unit having a first end connected to a negative electrode of the battery and a second end connected to the ground, wherein the second resistance unit is variably controllable between having a third resistance value or a fourth resistance value greater than the third resistance value; a voltage measurement unit configured to measure a voltage across the first resistance unit and a voltage across the second resistance unit; and an insulation resistance calculation unit configured to calculate a first insulation resistance value between the positive electrode of the battery and the ground and a second insulation resistance value between the negative electrode of the battery and the ground based on the first resistance value, the second resistance value, the third resistance value, the fourth resistance value and the voltage measured by the voltage measurement unit, wherein the first resistance unit includes a first resistance value unit that is ON/OFF controlled by a first switch and a second resistance value unit (R1, R2) that is ON/OFF controlled by a second switch, wherein the first and second resistance value units (R1, R2) are connected in parallel between the positive electrode of the battery and the ground, wherein the second resistance unit includes a third resistance value unit that is ON/OFF controlled by a third switch and a fourth resistance value unit that is ON/OFF controlled by a fourth switch, wherein the third and fourth resistance value units (R1, R2) are connected in parallel between the negative electrode of the battery and the ground, and characterized in that when the first switch or the second switch of the first resistance unit is ON, the insulation resistance calculation unit controls the third switch and the fourth switch of the second resistance unit to be OFF.