Provided is a valve type writing instrument, eliminating the need for frequently making a core pushing-in operation, thus being long-lasting, and causing no blurring of a written character. The valve type writing instrument includes an ink tank barrel; a valve housing cylinder, fitted into the ink tank barrel; and a core, slidably held in the valve housing cylinder, in which an ink reservoir member, reservoiring ink, and a valve unit case, incorporating a valve mechanism are loaded. The ink reservoir member has a truncated cone shape, a core insertion hole being formed so as to be penetrated through the central portion thereof, one half part of core being slidably housed therein, a number of slits for reservoiring ink being radially formed from the core insertion hole, and ink reservoired in the slits being capable of permeating into the housed portion of core in the core insertion hole as needed.