A connecting blade includes an insulation board having an adjustment region; and paired differential lines disposed on the insulation board. Each of the paired differential lines has contact points at both ends thereof for connecting to a circuit connecting member. The paired differential lines include a straight pair and a cross pair. The straight pair is formed of two first lines not crossing each other. The cross pair is formed of two second lines having a crossing region where the two second lines cross each other without contacting with each other. The cross pair is arranged so that the cross pair contacts with the adjustment region at least partially. The adjustment region has a specific size and a permittivity so that a signal transmission time lag between the cross pair and the straight pair is reduced.