PURPOSE: An air conditioner is provided to achieve an optimum vibration attenuating effect by controlling a vibration attenuating force to correspond the change of the vibration property of a pipe. CONSTITUTION: An air conditioner comprises: a pipe supporting device(20) which includes springs(33) which pressurize a pipe which is connected to a compressor, a solenoid valve(43) which controls the pressure of the spring, and a damper which respectively pressurizes the pipe from a plurality of directions; and a microcomputer which drives the solenoid valve and attenuates the vibration of the pipe if the operation frequency of the compressor is in the resonance frequency band of the pipe and which reduces the vibration of the pipe by increasing/decreasing the pressure of a plurality of the springs. The solenoid valve respectively controls the pressure of a plurality of springs.
