Fiber-reinforced polymer molded body

A fiber-reinforced polymer molded body which comprises a matrix polymer having a processing temperature lower than 220.degree. C. and at least one reinforcing layer of a molecularly oriented and silane-crosslinked ultra-high-molecular weight polyethylene fiber, wherein (i) said reinforcing layer is laminated with or embedded in the matrix in a state where the ends of said layer are restrained, said matrix being thermally formed or thermally cured, (ii) said fiber contains the grafted silane in an amount of 0.01 to 5% by weight as the content of Si based on the ultra-high-molecular weight polyethylene and has at least two crystal-melting peaks (Tp) at temperature higher by at least 10.degree. C. than the inherent crystal-melting temperature (Tm) of the ultra-high-molecular weight polyethylene obtained as the main melting peak at the second temperature elevation, when the fiber is analyzed in the constrained state by a differential scanning calorimeter, the melting calorific value of the crystal-melting peaks (Tp) being at least 50% of the total melting calorific value and the sum of calorific values of high temperature side melting peaks (Tp1) appearing at temperatures in the range of from (Tm+35.degree. C.) to (Tm+120.degree. C.) being at least 5% of the total melting calorific value, and (iii) the reinforcing layer substantially retains the orientation crystal structure of the ultra-high-molecular weight polyethylene fiber.