A construction machine and a projecting member thereof are provided which can be manufactured at low cost and restrict deformation of an operator's cab without impairing visibility in case of tumbling of the construction machine. To this end, there are provided, on a revolving superstructure frame (3), a work implement (30) located on the cross-wise mid position of a front part, a counterweight (7) located at a rear part and an operator's cab located at either the right or left side of the front part. At least one of the revolving superstructure frame, the work implement and the counterweight is provided with a projecting member (31-38) that projects outward. An operator's cab space (10a, 20a) is kept in an inner position of a vehicle body compared to a virtual plane defined by the at least one projecting member and positions where no projecting members are provided.