Foldable device with an automatic spreading positioning function

A foldable device, comprising:

• a support unit including a pivot base, two support shafts and a shaft member, said pivot base including a base seat, a through hole and two support holes, each of which extends through said base seat in a first direction, said support shafts respectively extending through said support holes and being pivotably connected with said base seat, said shaft member extending through said through hole and along a central axis, said shaft member being pivotably connected with said base seat to be rotatable relative to said base seat about a rotating axis which is transverse to a direction of the central axis, such that said shaft member is rotatable relative to said base seat between a ready position, where said shaft member extends parallel to the first direction, and a swung position, where said shaft member is inclined relative to the first direction by an inclined angle;
• and
• a biasing member interposed between said base seat and said shaft member to have a torque which urges said shaft member to rotate toward the swung position, wherein, when said shaft member is in the ready position, said support shafts extend parallel to said shaft member, and wherein, during rotation of said shaft member to the swung position, said shaft member actuates said support shafts to rotate and spread relative to said base seat and to be inclined and intersect one another.