Provided is a method for manufacturing a panel including a core having a truss structure between upper and lower face sheets. The manufacturing method includes disposing the upper and lower face sheets in parallel to each other at a predetermined distance, repeatedly performing, several times, a process in which a plurality of flexible wires vertically pass through the upper and lower face sheets to reciprocation-connect the upper and lower face sheets to each other, thereby sewing the upper and lower face sheets after the upper and lower face sheets horizontally move in parallel to each other, and maximally spacing both face sheets in a vertical direction while being maintained in a parallel to each other after a relative displacement of the upper and lower face sheets is solved, and fixing the face sheets and the wires to each other.