To provide a microneedle applicator which can be easily attached with the microneedle patch and is not likely to cause skin infection even when continuously administered to a large number of users.A microneedle patch application device comprising: a movable cylinder having an opening equipped with a clasp or a screw for attaching the microneedle patch case at one end； a case body connected with the other end of the movable cylinder； a piston disposed movably in a direction to the opening of the movable cylinder in the case body； a slide for sliding the piston in an opposite direction to the opening； a slide lock for locking the sliding of the slide in the opposite direction； a spring for applying an impact to the piston by the sliding in the opposite direction and the locking； a safety shaft for suppressing unlocking of the slide lock； and a trigger interlocked with the safety shaft. Although the microneedle patch case at the front end is pressed against a skin, it is replaced for each time of application.
