Provided is a microneedle device where a coating agent has been applied to microneedles having a biodegradable resin. It has been found that the application of the coating agent to microneedles of a biodegradable resin having a predetermined strength allows the microneedles to have excellent performance. Further, with regard to the coating agent, a predetermined type and amount thereof are also useful to demonstrate performance. Accordingly, when a microneedle device 1 is arranged so that at least a part of a microneedle array 2 provided with microneedles 3 made from polylactic acid having a weight average molecular weight of 40,000 or more is coated with a carrier containing physiologically active ingredients, it is possible to attain excellent migration characteristics of the physiologically active ingredients to a living body.