A high-frequency signal line includes a body with a first layer level and a second layer level; a signal line including a first line portion provided at the first layer level, a second line portion provided at the second layer level, and a first interlayer connection connecting the first line portion and the second line portion; a first ground conductor including a first ground portion provided at the first layer level; a second ground conductor including a second ground portion provided at the second layer level; and a second interlayer connection connecting the first ground portion and the second ground portion. A distance between the first interlayer connection and the second interlayer connection is not less than a maximum distance between the first line portion and the first ground portion and is not less than a maximum distance between the second line portion and the second ground portion.