<p>In a lattice boom (1), a first reinforcing lattice member (4) includes a first reinforcing pipe (34) which has a portion extending in the same direction as a first main member (10a) of a base boom (2) and which is separated outward from a first side surface of the base boom and a first mounting part (40) which is provided on the first reinforcing pipe and which is mounted to the first main member so as to transfer a load acting on the first main member in an axial direction of the first main member to the first reinforcing pipe, and a second reinforcing lattice member (6) includes a second reinforcing pipe (54) which has a portion extending in the same direction as a second main member (10b) of the base boom (2) and which is separated outward from a second side surface of the base boom and a second mounting part (60) which is provided on the second reinforcing pipe and which is mounted to the second main member so as to transfer a load acting on the second main member in an axial direction of the second main member to the second reinforcing pipe.</p>
