The purpose of the present invention is to provide an acrylic pressure sensitive adhesive and a pressure sensitive adhesive tape preferable to be used for adhesion and fixation of members to be used in closed space of such as a vehicle, a housing where odors become a problem; or in the side of electronic appliances where volatile gases become a problem and also relates to a vehicular air conditioner unit produced by using them.The present invention relates to an acrylic pressure sensitive adhesive, which has 500 ppm or lower of volatile component concentration A calculated by the following equation (1), when the acrylic pressure sensitive adhesive is heated at 90.degree. C. for 30 minutes: volatile component concentration A (ppm)=volatile component content X (.mu.g)/pressure sensitive adhesive weight Z (g) before heating (1)in the equation (1), the volatile component content X is an amount measured by conversion into toluene.