A pole base assembly for a magnetic recording/reproducing apparatus for guiding a tape drawn from a reel through a predetermined path in parallel or substantially in parallel toward a lead surface of a head drum. The pole base assembly comprises a pole base disposed to approach and retreat from a side of the head drum when the tape is loaded and unloaded, respectively, a sloping pole disposed to be sloped on the pole base, to be parallel or substantially parallel to the lead surface of the head drum, for guiding the tape fed to the head drum at a predetermined angle, to be parallel to the lead surface, and a supporting holder disposed on the pole base, and having a sloping part to support the sloping pole to be inclined at a predetermined angle.