Abstract: A variable pitch mechanism for a helicopter is configured to have a simple configuration with a small number of members, and to be capable of precisely controlling a pitch angle of blades without accurate adjustment. A pitch plate 16 and a pitch plate boss 17 are slidably mounted on an outer periphery of a main mast 61, and an output shaft of a servomotor 19 is directly connected to a pitch lever 18 that vertically moves the pitch plate boss 17. By actuating the servomotor 19 and rotating the pitch lever 18, the pitch plate boss 17 and the pitch plate 16 are displaced upward or downward along the main mast 61, thereby tilting blade holders 13, 13 connected to the pitch plate 16 and changing a pitch angle of the blades 14.