Provided is an adjustment unit for guitar effector that is installed between input unit and output unit to adjust a volume and a tone based on the output signal by using a variable resistor in an analog circuit. The adjustment unit comprises one or more of a level part that adjusts a size of the output signal, a tone part that adjusts an amount of high-pitched sound and an amount of low-pitched sound, and a distortion part that adjusts a degree of distortion, one or more of the level part, the tone part and the distortion part are plural, and a switch comprising one or more of a level switch for selecting any one of the plurality of level parts, a tone switch for selecting any one of the plurality of tone parts, and a distortion switch for selecting any one of the plurality of distortion parts is installed.