An automatic-switch nozzle head having two valve mouths, comprising: a main body having a through valve hole, a valve plug, an air supply hole disposed between two ends of the valve hole; a first connecting mouth having a first mouth hole; a second connecting mouth having a second mouth hole; and the valve plug being axially movable between a first position and a second position of the valve hole, characterized in that the valve plug being provided with a plurality of first clamping claws and a plurality of second clamping claws, a plurality of first restraint grooves being formed in between the first clamping claws to define a first restraint hole, the first restraint hole and the valve hole being coaxial, the first restraint hole being able to contract radially, the first restraint hole being adapted for the first connecting mouth to be coaxially inserted; a plurality of second restraint grooves being formed in between the second clamping claws to define a second restraint hole, the second restraint hole and the valve hole being coaxial, the second restraint hole being able to contract radially, the second restraint hole being adapted for the second connecting mouth to be inserted coaxially; wherein, when the valve plug is moved to the first position, the second clamping claws are released from the valve hole and the first clamping claws are compressed, such that the first restraint hole radially tighten the first connecting mouth for the air supply hole to communicate with the first mouth hole; when the valve plug is moved to the second position, the first clamping claws are released from the valve hole and the second clamping claws are compressed, such that the second restraint hole radially tighten the second connecting mouth for the air supply hole to communicate with the second mouth hole. a main body having a through valve hole, a valve plug, an air supply hole disposed between two ends of the valve hole; a first connecting mouth having a first mouth hole; a second connecting mouth having a second mouth hole; and the valve plug being axially movable between a first position and a second position of the valve hole, characterized in that the valve plug being provided with a plurality of first clamping claws and a plurality of second clamping claws, a plurality of first restraint grooves being formed in between the first clamping claws to define a first restraint hole, the first restraint hole and the valve hole being coaxial, the first restraint hole being able to contract radially, the first restraint hole being adapted for the first connecting mouth to be coaxially inserted; a plurality of second restraint grooves being formed in between the second clamping claws to define a second restraint hole, the second restraint hole and the valve hole being coaxial, the second restraint hole being able to contract radially, the second restraint hole being adapted for the second connecting mouth to be inserted coaxially; wherein, when the valve plug is moved to the first position, the second clamping claws are released from the valve hole and the first clamping claws are compressed, such that the first restraint hole radially tighten the first connecting mouth for the air supply hole to communicate with the first mouth hole; when the valve plug is moved to the second position, the first clamping claws are released from the valve hole and the second clamping claws are compressed, such that the second restraint hole radially tighten the second connecting mouth for the air supply hole to communicate with the second mouth hole.