PURPOSE: To prevent the outflow of a liquid due to careless pressing of a head, by engaging the latch groove provided to the protruded part of a cap and the engaging protrusion provided to the head at the falling position of a piston to limit the rising operation of the piston.

CONSTITUTION: In a dispenser 10 sucking up the liquid accommodated in a container 29 by sliding a piston 14 to introduce the same into a cylinder 12 as well as flowing out the same under pressure, a protruded part 30 having a latch groove 31 is formed to the cap 24 attached to the mouth part of the container 29. On the other hand, to a head 36 which is attached to the upper end part of the piston 14 and integrally operated with the piston 14, an engaging protrusion 44 capable of being engaged with the latch groove 31 of the protruded part 30 at the falling position of the piston 14 is formed. That is, by engaging the latch groove 31 of the protruded part 30 and the engaging protrusion 44 at the falling position of the piston 14, the rising operation of the piston 14 is limited.