An electronic device comprising: a main body housing comprising a first plate disposed to face a first direction, a second plate disposed to face a second direction which is opposite to the first direction, and a plurality of side members (11a, 11b, 114) disposed between the first plate and the second plate, the plurality of side members including a first side member, a second side member, and a third side member; a support frame disposed to overlap at least a partial area of the first plate, and sliding in a direction away from the main body housing or sliding in a direction toward the main body housing; a flexible display disposed on at least a part of the main body housing, connected to the support frame, and extending a display area according to movement of the support frame, and at least one or more speakers (115, 116) disposed in the main body housing, and emitting sound toward the second plate and the side members (11a, 11b, 114), wherein at least one or more first speaker holes for emitting the sound of the speaker are formed in the first side member, wherein at least one or more second speaker holes for emitting the sound of the speaker are formed in the second side member and wherein at least one or more third speaker holes for emitting the sound of the speaker are formed in a first area of the second plate, wherein the at least one or more third speaker holes are configured to be opened and closed by a first portion (121, 122) of the support frame according to the movement of the support frame. a main body housing comprising a first plate disposed to face a first direction, a second plate disposed to face a second direction which is opposite to the first direction, and a plurality of side members (11a, 11b, 114) disposed between the first plate and the second plate, the plurality of side members including a first side member, a second side member, and a third side member; a support frame disposed to overlap at least a partial area of the first plate, and sliding in a direction away from the main body housing or sliding in a direction toward the main body housing; a flexible display disposed on at least a part of the main body housing, connected to the support frame, and extending a display area according to movement of the support frame, and at least one or more speakers (115, 116) disposed in the main body housing, and emitting sound toward the second plate and the side members (11a, 11b, 114), wherein at least one or more first speaker holes for emitting the sound of the speaker are formed in the first side member, wherein at least one or more second speaker holes for emitting the sound of the speaker are formed in the second side member and wherein at least one or more third speaker holes for emitting the sound of the speaker are formed in a first area of the second plate, wherein the at least one or more third speaker holes are configured to be opened and closed by a first portion (121, 122) of the support frame according to the movement of the support frame. wherein at least one or more first speaker holes for emitting the sound of the speaker are formed in the first side member, wherein at least one or more second speaker holes for emitting the sound of the speaker are formed in the second side member and wherein at least one or more third speaker holes for emitting the sound of the speaker are formed in a first area of the second plate, wherein the at least one or more third speaker holes are configured to be opened and closed by a first portion (121, 122) of the support frame according to the movement of the support frame.