Joint structure for vehicle body

A joint structure for a vehicle body, the joint structure comprising:

• a front body module that is a stationary part fixed to a front part of an under body of the vehicle body;
• a rear body module that is a variable part having a preset shape, the rear body module being attachable to and detachable from a rear part of the under body and a rear part of the front body module;
• a stationary part center roof rail disposed on an upper portion of a rear edge of the front body module and extending in a direction perpendicular to a longitudinal direction of the vehicle body;
• a plurality of stationary part coupling modules disposed on the stationary part center roof rail at an upper end surface portion of the rear edge of the front body module;
• and
• a plurality of variable part coupling modules disposed on an upper end surface portion of a front edge of the rear body module and couplable to the stationary part coupling modules by an electromagnetic force.