Side door structure of vehicle

A side door structure of a vehicle, comprising:

• an outer member;
• an inner member connected to said outer member and including a front-side vertical wall portion and a rear-side vertical wall portion which are positioned respectively at a front side and a rear side, in a vehicle longitudinal direction, of the inner member, the front-side vertical wall portion being provided with a hinge rotatable relative to a vehicle body, the rear-side vertical wall portion being provided with a latch device capable of locking or unlocking relative to the vehicle body;
• an impact bar provided to extend from a front-side attachment portion which is formed at said front-side vertical wall portion to a rear-side attachment portion which is formed at said rear-side vertical wall portion;
• a hinge-reinforcement member connected to said hinge and reinforcing a hinge attachment portion where the hinge is attached to said front-side vertical wall portion;
• and
• a latch-reinforcement member connected to said latch device and reinforcing a latch-attachment portion where the latch device is attached to said rear-side vertical wall portion,
• wherein at least one of said front-side vertical wall portion and said rear-side vertical wall portion is configured as a cast or resin-made vertical wall portion which is made by casting or of high-strength resin, and said hinge-reinforcement member and/or said latch-reinforcement member which are provided at said respective cast or resin-made vertical wall portion are configured to have higher ductility than the cast or resin-made vertical wall portion and connected to said impact bar.