To provide a method for manufacturing a thick pultruded item which can effectively produce a thick pultruded item showing no swell in the thickness direction and having uniform thickness.

A method for manufacturing a thick pultruded item comprises a step of shaping and heating a forming material 3 obtained by impregnating a fiber base material with an uncured thermosetting resin by making the forming material 3 pass through a forming aperture 211 of a pultruding die 21 having a cross sectional inner shape corresponding to a cross sectional outer shape of the thick pultruded item to be formed and continuously pultruding the thick pultruded item 4 having a cured outer layer portion and a half-cured central portion and a step of clamping the thick pultruded item 4 in its thickness direction for a predetermined period with a pressure holding die 221 to keep the thickness of the formed item immediately after being pultruded from the die, moving it in the pultruding direction and curing its central portion by use of an pressure holding apparatus 21 having the pressure holding die 221 moving in the pultruding direction in liaison with the pultruding velocity and thereafter removing the pressure holding die 221.