Side door structure for vehicle

A side door structure for a vehicle (1) is composed of a main body (10) and a rear side reinforcing member (31) provided in the main body (10). The main body (10) is formed by an inner panel (15) and an outer panel (11) connected to the inner panel (15). The rear side reinforcing member (31) connects the inner panel (15) and the outer panel (11) in the main body (10), and the rear side reinforcing member (31) forms a rigid part with a closed hollow cross section at a rear part of the main body (10) by the cooperation with the inner panel (15) and the outer panel (11).