An adjustable inflatable neck support device, comprising: a center support body having a top surface configured to support a neck of a user and a bottom surface concavely provided with a first chamber; a first inflatable airbag configured to be accommodated within the first chamber, expand or contract along a displacement axis, and displace the top surface of the center support body along the displacement axis; two second inflatable airbags, each configured to be accommodated within a corresponding one of second chambers that are concavely provided on the bottom surface of the neck support device and located at opposite sides of the first chamber, expand or contract along the displacement axis, and displace a top surface of the neck support device along the displacement axis; and an inflation device configured to be connected to the first inflatable airbag and the second inflatable airbags, respectively, and inflate or deflate the first inflatable airbag and the second inflatable airbags to change expansion or contraction degrees of the first inflatable airbag and the second inflatable airbags, wherein the neck support device is divided into at least a supporting portion (S 1) including the center support body and the first inflatable airbag and a bearing portion configured to bear an occiput of a user when the user is in a supine position, and further comprises a pillowcase and a plurality of physical therapy portions fastened to the pillowcase; a height of a top surface of the bearing portion is lower than a height of a top surface of the supporting portion; and at least one of the physical therapy portions is fastened to a position on the pillowcase that corresponds to a position of the center support body, and is configured to abut against the neck of the user and be electrically connected to a physical therapy device to receive electric power transmitted from the physical therapy device. a center support body having a top surface configured to support a neck of a user and a bottom surface concavely provided with a first chamber; a first inflatable airbag configured to be accommodated within the first chamber, expand or contract along a displacement axis, and displace the top surface of the center support body along the displacement axis; two second inflatable airbags, each configured to be accommodated within a corresponding one of second chambers that are concavely provided on the bottom surface of the neck support device and located at opposite sides of the first chamber, expand or contract along the displacement axis, and displace a top surface of the neck support device along the displacement axis; and an inflation device configured to be connected to the first inflatable airbag and the second inflatable airbags, respectively, and inflate or deflate the first inflatable airbag and the second inflatable airbags to change expansion or contraction degrees of the first inflatable airbag and the second inflatable airbags, wherein the neck support device is divided into at least a supporting portion (S 1) including the center support body and the first inflatable airbag and a bearing portion configured to bear an occiput of a user when the user is in a supine position, and further comprises a pillowcase and a plurality of physical therapy portions fastened to the pillowcase; a height of a top surface of the bearing portion is lower than a height of a top surface of the supporting portion; and at least one of the physical therapy portions is fastened to a position on the pillowcase that corresponds to a position of the center support body, and is configured to abut against the neck of the user and be electrically connected to a physical therapy device to receive electric power transmitted from the physical therapy device.