A foldable display device including at least one folding area disposed between two non-folding areas (NFA1, NFA2) arranged in a first direction, the foldable display device comprising: a display module which is flexible; a first supporter and a second supporter disposed under the display module, attached to the display module and arranged in the first direction wherein the first supporter is disposed under one of the non-folding areas and the second supporter is disposed under the other one of the non-folding areas; spacers disposed between the first supporter and the second supporter; a third supporter and a fourth supporter respectively disposed under the first supporter and the second supporter; a first side of the third supporter and a first side of the fourth supporter face each other in the first direction, a distal side of the third supporter is opposite to the first side of the third supporter and a distal side of the fourth supporter is opposite to the first side of the fourth supporter; hinge parts connected to the third supporter and the fourth supporter and respectively disposed at both sides of the supporters (SP1-SP4), which sides are opposite to each other in a second direction crossing the first direction, wherein the hinge parts provide at least one folding axis extending in the second direction and the hinge parts are configured to fold the supporters (SP1-SP4) and the display module with respect to the folding axis in the folding area of the foldable display device; grooves defined at portions where the first side of the third supporter is connected to a second side and a third side of the third supporter and at portions where the first side of the fourth supporter is connected to a second side and a third side of the fourth supporter, wherein the second side and the third side of the third supporter are opposite to each other in the second direction, the second side and the third side of the fourth supporter are opposite to each other in the second direction, the grooves extend in the second direction, and the spacers are disposed in the grooves; sliding parts (SU1, SU2) disposed in openings (OP1, OP2) defined in the third supporter and the fourth supporter and connected to the first supporter and the second supporter; and elastic parts (EU1, EU2) disposed in guide grooves (GG1, GG2) defined in the third supporter and the fourth supporter and extending in the first direction from the openings (OP1, OP2) toward the distal side of the third supporter and the distal side of the fourth supporter, wherein the elastic parts (EU1, EU2) contact sides of the sliding parts (SU1, SU2) facing the distal sides (S3, S4) of the third and fourth supporters (SP3, SP4). a display module which is flexible; a first supporter and a second supporter disposed under the display module, attached to the display module and arranged in the first direction wherein the first supporter is disposed under one of the non-folding areas and the second supporter is disposed under the other one of the non-folding areas; spacers disposed between the first supporter and the second supporter; a third supporter and a fourth supporter respectively disposed under the first supporter and the second supporter; a first side of the third supporter and a first side of the fourth supporter face each other in the first direction, a distal side of the third supporter is opposite to the first side of the third supporter and a distal side of the fourth supporter is opposite to the first side of the fourth supporter; hinge parts connected to the third supporter and the fourth supporter and respectively disposed at both sides of the supporters (SP1-SP4), which sides are opposite to each other in a second direction crossing the first direction, wherein the hinge parts provide at least one folding axis extending in the second direction and the hinge parts are configured to fold the supporters (SP1-SP4) and the display module with respect to the folding axis in the folding area of the foldable display device; grooves defined at portions where the first side of the third supporter is connected to a second side and a third side of the third supporter and at portions where the first side of the fourth supporter is connected to a second side and a third side of the fourth supporter, wherein the second side and the third side of the third supporter are opposite to each other in the second direction, the second side and the third side of the fourth supporter are opposite to each other in the second direction, the grooves extend in the second direction, and the spacers are disposed in the grooves; sliding parts (SU1, SU2) disposed in openings (OP1, OP2) defined in the third supporter and the fourth supporter and connected to the first supporter and the second supporter; and elastic parts (EU1, EU2) disposed in guide grooves (GG1, GG2) defined in the third supporter and the fourth supporter and extending in the first direction from the openings (OP1, OP2) toward the distal side of the third supporter and the distal side of the fourth supporter, wherein the elastic parts (EU1, EU2) contact sides of the sliding parts (SU1, SU2) facing the distal sides (S3, S4) of the third and fourth supporters (SP3, SP4).