PURPOSE: To simplify the assembling by forming a bevel gear to a peripheral plane of a varible condenser drum fitted to a variable condenser shaft and forming a spur gear to a peripheral side face to drive the variable condenser shaft and a pointer at the same time in turning a tuning knob.

CONSTITUTION: In turning the tuning knob 8, the varible condenser shaft 4-1 is driven by meshing between the tuning shaft 6, the variable condenser drum 5 and the bevel gears 6-1, 5-1 and also the pointer 7 is slided by meshing between the variable condenser drum 5, the pointer 7 and the spur gears 5-2, 7-1. A variable condenser drum press contact rib 3-4 is provided to a dial chassis 3 so as not to cause a gap to the meshing part between the bevel gears 5-1, 6-1 thereby preventing the turning backlash between the turning shaft 6 and the variable condenser shaft 4-1. Since the variance in the height of the variable condenser 4 is large, the variance in the height of the variable condenser drum 5 is absorbed by connecting the bevel gear 5-1 being the engagement part of the variable condenser shaft 4-1 and the engagement part with the tuning shaft 6 with the thin rib 5-4 so as to utilize the elasticity of the resin of the variable condenser drum 5 itself.