A device for inserting needles of a microneedle patch into a skin includes a housing. The housing includes a support portion for supporting a microneedle patch, a pressure-receiving portion to which the user applies a force to press the microneedle patch against the skin, and a plurality of leg portions each having at its one end a connecting portion connected to the pressure-receiving portion and having at its other end a tip portion coming into contact with the skin. The housing is designed to deform when a force is applied to the pressure-receiving portion, to cause a tension in a portion of the skin facing the support portion.