An air conditioner comprising: a prefilter made of a flexible material, the prefilter being disposed to face an air suction hole through which air is suctioned; a roller configured to support one side of the prefilter in a longitudinal direction, the roller being configured to allow the prefilter to move in a left-right direction; a roller rotation mechanism configured to allow the roller to rotate; a brush unit disposed to contact the prefilter when the roller rotates, the brush unit being spaced apart from the roller rotation mechanism; a filter case in which the air suction hole is defined and which has a space in which the prefilter is accommodated; a main body provided with an upper housing on which the filter case is separably mounted; characterized in that the air conditioner furthermore comprising: an electrostatic dust filter disposed between the prefilter and the filter case and spaced apart from the roller; at least one of electrode terminals (353 and 354) provided to the electrostatic dust filter; and at least one of supply terminals (121 and 122) configured to contact the at least one of electrode terminals (353 and 354) and disposed in the upper housing; wherein a terminal hole through which at least one of the electrode terminals (353 and 354) or the supply terminals (121 and 122) is configured to pass is defined in the filter case. a prefilter made of a flexible material, the prefilter being disposed to face an air suction hole through which air is suctioned; a roller configured to support one side of the prefilter in a longitudinal direction, the roller being configured to allow the prefilter to move in a left-right direction; a roller rotation mechanism configured to allow the roller to rotate; a brush unit disposed to contact the prefilter when the roller rotates, the brush unit being spaced apart from the roller rotation mechanism; a filter case in which the air suction hole is defined and which has a space in which the prefilter is accommodated; a main body provided with an upper housing on which the filter case is separably mounted; characterized in that the air conditioner furthermore comprising: an electrostatic dust filter disposed between the prefilter and the filter case and spaced apart from the roller; at least one of electrode terminals (353 and 354) provided to the electrostatic dust filter; and at least one of supply terminals (121 and 122) configured to contact the at least one of electrode terminals (353 and 354) and disposed in the upper housing; wherein a terminal hole through which at least one of the electrode terminals (353 and 354) or the supply terminals (121 and 122) is configured to pass is defined in the filter case. an electrostatic dust filter disposed between the prefilter and the filter case and spaced apart from the roller; at least one of electrode terminals (353 and 354) provided to the electrostatic dust filter; and at least one of supply terminals (121 and 122) configured to contact the at least one of electrode terminals (353 and 354) and disposed in the upper housing; wherein a terminal hole through which at least one of the electrode terminals (353 and 354) or the supply terminals (121 and 122) is configured to pass is defined in the filter case.