Printed wiring board

A printed wiring board comprising:

• an insulating substrate;
• a first signal line formed on the insulating substrate;
• a second signal line having a shorter length than a length of the first signal line;
• and
• a ground layer comprising a first region and a second region, wherein
• the first region is defined based on a position of the first signal line and has a first predetermined width,
• the second region is defined based on a position of the second signal line and has a second predetermined width,
• parts of the ground layer are removed in the first region and the second region, wherein a first ratio of a surface area of the ground layer remaining in the first region to a total surface area of the first region is lower than a second ratio of a surface area of the ground layer remaining in the second region to a total surface area of the second region, and
• the first predetermined width of the first region is three times or more of a width of the first signal line, the second predetermined width of the second region being three times or more of a width of the second signal line.