Printed circuit board (PCB) design support apparatus and method are provided. The target element disposed on a front surface of the printed circuit board is mirror-copied, and then the straight line distance between the mirror copied element and a back element disposed on the back surface of the PCB is calculated under the condition that the thickness of the PCB is zero. The resultant creepage distance between the target element and the back element is obtained by adding the thickness of the PCB to the straight line distance. The creepage distance can be obtained accurately and quickly by a calculation on a straight line distance.