A solid-state image pickup apparatus includes an image pickup device electrically connected to a flexible printed board, a rigid board electrically connected to an image pickup device via the flexible printed board, and a signal cable incorporating a plurality of coaxial lines. The rigid board includes a first surface including a core-wire connecting section to which core wires of the coaxial lines are connected and a second surface including an external-conductor connecting section to which external conductors of the coaxial lines are connected and including a step having a height dimension substantially the same as a dimension difference between an outer diameter section of the core wires and an outer diameter section of the external conductors of the coaxial lines substantially parallel to the first surface. The plurality of coaxial lines are connected substantially in parallel to the first and second surfaces of the rigid board.