To simplify a procedure to install a pedestal and knob and prevent them from being rotated by providing pin projecting from the back side of a knob to be installed on the front side of a door by a screw and by setting the pin into the door.

A screw 4 is driven from the back side through a lower hole provided in a door 1 and also through a hole provided in a pedestal 2 on the front face of the door 1, to go into a threaded hole 9 provided in a knob 3 from the back side, to fix the knob. A pin 5 projecting from the knob 3 is driven into a connecting hole 6, provided above a lower hole 7 and piercing the pedestal 2, to go into the door 1, where the connecting hole 6 has a circular cross-section and a smaller diameter than the lower hole 7. Therefore, the knob 3 is set at a given position on the door 1, when the pin 5 is driven into the connecting hole 6. The pin 5 projecting from the knob 3 is used to position the knob 3 and the pedestal 2 simultaneously, saving a pin on the pedestal 2 to position it, and thereby simplifying structure of the pedestal 2.