The aerial work platform C1, C2 is aimed at being associated to a self-moving operating machine and includes: a fixed central body (1 ), rectangular in plan view, provided with two guard sides (2), located at its long sides (LA) and a central platform (3), situated at the bottom; at least one extension module (10), hinged to said central body (1 ) at one of its smaller sides (LB), consisting of a three side structure (21 ), (22), (23), that defines, together with said smaller side (LB), an articulated parallelogram on a horizontal plane, aimed at assuming two configurations, respectively, flattened rest configuration (X), in which said three sides (21), (22), (23) are folded and placed against said fixed central body (1 ), and an open working one (V), in which the same three sides (21 ), (22), (23) are arranged at an angle one to another to define a side body (20), set beside and aligned with said fixed central body (1 ). A side platform (30), positioned in the side body (20), is beside and aligned with said central platform (3). Locking means (40), aimed at stabilizing said open work configuration (V) of said extension module (10), are provided between the side platform (30) and said sides (21 ), (22), (23) of the structure.