To easily mount and demount the blades to a hub by providing the clearance for accomodating a claw in a groove, and a projecting part mounted on the clearance, extended outward, and engageable with a lower side of the claw.

An ordinary propeller hub is rotatably mounted on an adjustment plate, that is, a blade supporting plate 1, and can be displaced in the angular direction on an radial axis 2 of a variable pitch propeller. A hub ordinarily comprises two blade supporting plates, but can comprise three or more blade supporting plates optionally. The axes 2 in the radial direction of the hub are positioned at equal intervals in the angular direction on the axis of the hub. An upper side 3 of each blade supporting plate 1 is flat, and comprises two claws 4 projecting inward in the radial direction, extended along the peripheral direction of each blade supporting plate 1, and faced to each other in the diameter direction. The clearance is formed between the claws and the upper side of the blade supporting plate.