A trigger-type pump dispenser capable of preventing deformation of a channel of a coupling part when a piston is vertically pushed down by a trigger even in a structure in which the coupling part bends and a nozzle does not vertically move. The dispenser has a base main body 1 having the cylinder part 11 inside and attachable to an opening part of a container main body. A cover body 4 detachably latched with the base main body. A piston structure 2 composed of the nozzle part 21 engaged with the base main body, the piston part 23, and a bendable coupling part coupling the nozzle part and the piston part. Many fins 22A are formed on the periphery of the coupling part 22 so that an interior channel is not deformed.