Provided are a control switch mechanism, a trigger switch, and an electric tool, having vibration resistance and durability and capable of preventing malfunction. The control switch mechanism (20) includes an optical sensor (21) having a light emitting element (21a) and a light receiving element (21b), and a reflector (22) that increases or decreases an amount of light received by the light receiving element (21b). An increase and a decrease in output of an operation device are controlled along with an increase and decrease in amount of light received by the light receiving element (21b) due to relative movement between the optical sensor (21) and the reflector (22).