A portable air purifier , comprising: a housing provided with an entrance part configured to suction air, provided therein with a filter part and a fan module , and forming an air flow path in an up-down direction; a discharge part disposed at an outlet of the housing and configured to guide a discharge direction of air; a rotation supporter which is connected to the housing , movement of which is restricted and which supports the discharge part in a rotatable manner; and a rotation guide disposed respectively at the discharge part and the rotation supporter and configured to guide rotation of the discharge part to allow the discharge part to rotate within predetermined angles, wherein the rotation supporter comprises: a core member disposed on a lower side of the discharge part and extended from a center of the outlet to the discharge part ; a core supporter which is extended outside the core member , which is fixed to an inside of the housing and movement of which is restricted together with movement of the core member ; and a ball joint , a lower side of which is coupled to the core member and movement of which is restricted, and an upper side of which is inserted into the discharge part and supports the discharge part in a rotatable manner, and characterized in that the rotation guide comprises: a guide projection connected to the ball joint or integrated with the ball joint , and protruding outside the ball joint ; a guide groove forming a concave groove inside the discharge part facing the guide projection ; and wherein the guide projection is inserted into the guide groove , and a rotation of the discharge part at a predetermined angle or greater is restricted since the guide projection is held inside the guide groove . a housing provided with an entrance part configured to suction air, provided therein with a filter part and a fan module , and forming an air flow path in an up-down direction; a discharge part disposed at an outlet of the housing and configured to guide a discharge direction of air; a rotation supporter which is connected to the housing , movement of which is restricted and which supports the discharge part in a rotatable manner; and a rotation guide disposed respectively at the discharge part and the rotation supporter and configured to guide rotation of the discharge part to allow the discharge part to rotate within predetermined angles, wherein the rotation supporter comprises: a core member disposed on a lower side of the discharge part and extended from a center of the outlet to the discharge part ; a core supporter which is extended outside the core member , which is fixed to an inside of the housing and movement of which is restricted together with movement of the core member ; and a ball joint , a lower side of which is coupled to the core member and movement of which is restricted, and an upper side of which is inserted into the discharge part and supports the discharge part in a rotatable manner, and a core member disposed on a lower side of the discharge part and extended from a center of the outlet to the discharge part ; a core supporter which is extended outside the core member , which is fixed to an inside of the housing and movement of which is restricted together with movement of the core member ; and a ball joint , a lower side of which is coupled to the core member and movement of which is restricted, and an upper side of which is inserted into the discharge part and supports the discharge part in a rotatable manner, and a guide projection connected to the ball joint or integrated with the ball joint , and protruding outside the ball joint ; a guide groove forming a concave groove inside the discharge part facing the guide projection ; and wherein the guide projection is inserted into the guide groove , and a rotation of the discharge part at a predetermined angle or greater is restricted since the guide projection is held inside the guide groove . <EOS>