Abstract: An extrusion method for obtaining a long phenolic resin pipe having excellent heat resistance by using an extruder having a screw, a cylinder, a die and a mandrel, the mandrel being inserted into a through-hole formed in the screw along the screw axis and protruding into the die along the screw axis, the die satisfying the following formulasR.sub.1 /R.sub.2 =0.25.about.1.0S.sub.1 /S.sub.2 =0.1.about.2.5where R.sub.1 is an outside diameter of the die flow path at the die outlet, S.sub.1 is a cross-sectional area of the die flow path at the die outlet, R.sub.2 is an outside diameter of the die flow path at the die inlet, and S.sub.2 is a cross-sectional area of the die flow path at the die inlet, and the inclination of the outer periphery of the die flow path portion from the die inlet to a starting point of the uniform flow path portion having the same cross section as the die outlet is not larger than 35.degree.