To provide a control cam mounting structure of such a configuration that a control cam furnished with a pointer or graduations and a reference member are arranged in non-restrained condition in the rotating direction with respect to a cam shaft whereby the control cam mounting phase with respect to the cam shaft is made adjustable without allowing the reference member to turn together.

Rotation of the cam shaft 2 is transmitted from a pair of washers 20... in the condition restrained at the cam shaft 2 about the rotating direction to limit switch cams (control cam) 3 and 4 installed in the non- restrained condition so that switches 5 and 6 are actuated for controlling any member to be controlled. The mounting phases of control cams 3 and 4 with respect to the cam shaft 2 are varied through relative sliding with the washers 20.... Dials 53 and 56 as reference members installed in the non-restrained condition from the cam shaft 2 are separated by the washer 20 from the control cam and will not turn together with the control cams 3 and 4.