PURPOSE: To provide the title novel polymer, a urea linkage-contg. polyurea, with specified proportion of specific group introduced into the resin skeleton, soluble in organic solvents, outstanding in heat resistance, mechanical properties, etc., useful as an adhesive, etc.

CONSTITUTION: The objective polymer having constituent structure of formula I [m is number of recurring units; X is such as to contain 35-100mol% of a structural unit of formula II (R is H, CH3 or C2H5)], ≥0.4dl/g in intrinsic viscosity (η inh) determined in the form of a DMF solution with a concentration of 0.5g/100ml at 30°C. It is suggested that this polymer be obtained by polyaddition reaction at 90-120°C between equal amounts of a diamine such as 9,9-bis(4-aminophenyl) fluorene and a diisocyanate in a solvent such as a mixed solvent comprising dioxane and dimethylsulfoxide.