A side knock type feeding mechanism for feeding an object to be fed inside a body by side knock. A front barrel which houses an object to be fed and is capable of feeding the object to be fed from a tip end opening, a knock button provided on a side portion of the front barrel so as to project and retract with respect to the front barrel, a rotary member which is inside the front barrel, rotates in a predetermined direction by knock of the knock button as a result that the knock button works, and rotates in an opposite direction by releasing the knock, a piston for feeding out the object to be fed, and a conversion mechanism for converting the rotation of the rotary member into a forward travelling motion of the piston in an axial direction inside the front barrel.