The present application provides a
processing method of a bonded substrate, which can
expose a part of a terminal portion of each bonded substrate in a state of a mother substrate. The
processing method of a bonded substrate of a first substrate and a second substrate includes the following steps: setting a removal target portion, which is perpendicular to an extension direction of a non-contact space between the first substrate and the second substrate, narrower toward the non-contact space, at a portion of the second substrate along the non-contact space; a scribing step of forming a scribe line on a non-bonding surface of the second substrate and extending a crack from the scribe line along a boundary surface of the removal target portion; a breaking step of abutting a breaking rod from the first substrate side and further extending the crack to separate the removal target portion from the second substrate at the boundary surface; and a removal step of removing the separated removal target portion to
expose a portion of the non-contact space in the first substrate.