To provide an excellent trigger type liquid jetting pump in which erroneous trigger operation on unuse is surely prevented to eliminate careless liquid leakage or the like and which is convenient to handle on use and is simple in structure.

This pump has a locking member E consisting of a pair of right and left oscillating arms 7 and a locking plate 8. The arms 7 extend back and forth on both sides of a cover 4 and inner surfaces thereof are attached pivotally to the outer surface of the cover and the inner surfaces behind the pivotally attached parts thereof are engaged with the outer surface of the cover through uneven locking means. The locking plate 8 connects the front end parts of the oscillating arms 7 and the front surface thereof is abutted on and engaged with the rear surface of a trigger D.