To provide a tubular body including at least a polyimide resin layer containing a predetermined amount of a thermally conductive inorganic filler or fibrous filler, the tubular body being easily removed from a form even when there is a difference between the inner diameter at the end thereof and the inner diameter at the central part by adjusting the difference between the inner diameter at the end and the inner diameter at the central part to a predetermined ratio.

The tubular body includes at least a polyimide resin layer containing a polyimide resin, a thermally conductive inorganic filler and a fibrous filler. With respect to 100 pts.wt. of the polyimide resin, the thermally conductive inorganic filler is included by 30 to 150 pts.wt., and the fibrous filler is included by 1 to 10 pts.wt. The ratio of the absolute value (ΔR) of the difference of the inner diameter (R1) and the inner diameter (R2) with respect to the larger one of the inner diameter at the end of the tubular body (R1) and the inner diameter of the central part (R2) is 0.01 to 0.45%.