A resin substrate combined structure includes a first resin substrate including a flexible resin defining a main material and includes a first portion, a second resin substrate including a flexible resin defining a main material and includes a second portion spaced from the first portion in a thickness direction, and an insulating member that envelops the first portion and the second portion while retaining a relative positional relationship between the first portion and the second portion. The insulating member includes a material with a higher rigidity than any of the main material of the first resin substrate and that of the second resin substrate.