Manual piston pump having a lockable dispensing head, having a cylinder, an inner locking sleeve forming a cylindrical passage for a hollow piston rod, one end of this extending into a pump chamber of the cylinder and the other end carrying the dispensing head, which is provided with an outer shaft section. A spring presses the piston rod outwards in relation to the cylinder, into a rest position, and in opposition to the spring the piston rod may be lowered by pressing on the dispensing head to dispense substance. To block the dispensing head at least one projection can be placed in engagement with a recess, and the recess has a latching lug arranged on a resilient web articulatedly mounted at the end side and can be latched as a joining partner to the projection.