A protective member mountable to an aerial vehicle having a body and at least one rotor held on the body, the protective member comprising: a plurality of support members that are connectable to the aerial vehicle and have a flexible member stretched between distal end portions thereof so as to surround an outside of the body, wherein at least one of the plurality of support members has a tension adjusting mechanism that is capable of adjusting a tension applied to the flexible member in a stretching direction, by changing a distance from a center of the body to the distal end portion, wherein the at least one of the plurality of support members has: a fastenable part that is configured to be fastened to the aerial vehicle; and a movable part that has a proximal end portion overlapping with, and held on, the fastenable part, and has a distal end portion holding the flexible member, and the tension adjusting mechanism is configured to adjust an overlap length between the movable part and the fastenable part, wherein the tension adjusting mechanism is configured as a mechanism for engaging the movable part with the fastenable part, wherein the tension adjusting mechanism has an outer thread that is formed on a distal end portion of the fastenable part, and a socket portion that is provided in a proximal end portion of the movable part and has an inner thread engageable with the outer thread, the movable part holding, on a distal end side thereof, the flexible member via an extension part and a mounting part, such that a length in which the inner thread engages with the outer thread can be adjusted, hence allowing the distance from the center of the body to the distal end portion of the support member, and thus to the mounting part, to be changed. a plurality of support members that are connectable to the aerial vehicle and have a flexible member stretched between distal end portions thereof so as to surround an outside of the body, wherein at least one of the plurality of support members has a tension adjusting mechanism that is capable of adjusting a tension applied to the flexible member in a stretching direction, by changing a distance from a center of the body to the distal end portion, wherein the at least one of the plurality of support members has: a fastenable part that is configured to be fastened to the aerial vehicle; and a movable part that has a proximal end portion overlapping with, and held on, the fastenable part, and has a distal end portion holding the flexible member, and the tension adjusting mechanism is configured to adjust an overlap length between the movable part and the fastenable part, wherein the tension adjusting mechanism is configured as a mechanism for engaging the movable part with the fastenable part, wherein the tension adjusting mechanism has an outer thread that is formed on a distal end portion of the fastenable part, and a socket portion that is provided in a proximal end portion of the movable part and has an inner thread engageable with the outer thread, the movable part holding, on a distal end side thereof, the flexible member via an extension part and a mounting part, such that a length in which the inner thread engages with the outer thread can be adjusted, hence allowing the distance from the center of the body to the distal end portion of the support member, and thus to the mounting part, to be changed.