An apparatus for heating washer liquid, may include a PTC (“Positive Temperature Coefficient”) heater provided in an air conditioning system of a vehicle, a subsidiary washer tank connected to a washer tank of the vehicle, and divided into a non-heated washer-liquid storage space for storing non-heated washer liquid received from the washer tank and a heated washer-liquid storage space for storing washer liquid which may be heated, a washer liquid circulation pump provided on the subsidiary washer tank, feeding the non-heated washer liquid into the PTC heater, and recovering the heated washer liquid to the heated washer-liquid storage space of the subsidiary washer tank, a washer liquid heating pipe fluid-connected to the washer liquid circulation pump and provided to pass through a heat radiation fin of the PTC heater so that the non-heated washer liquid fed by the washer liquid circulation pump may be selectively heated by the heat radiation fin provided in the PTC heater, and a washer liquid spray pump feeding the heated washer liquid, which may be stored in the heated washer-liquid storage space, to a spray nozzle.