A droplet ejecting apparatus, including: a head unit including (a) a cavity unit constituted by plate members stacked on and adhered to each other, having a first and a second outer surface respectively defined by a first and a second outermost plate member of the plate members which are opposite to each other and one of which has nozzles, and having liquid flow channels formed therein and respectively communicating with the nozzles, and (b) an actuator attached to the cavity unit and operable such that the head unit ejects droplets through the nozzles, a holder holding the head unit, a reinforcing plate adhered to the cavity unit so that the holder holds the head unit, an adhesive layer between the first outer surface and a first surface of the reinforcing plate as one of opposite surfaces thereof so as to adhere the cavity unit and the reinforcing plate to each other, and having a non-adhesive area in which no adhesive exists, and a measuring section configured such that a measurement for estimating a thickness of the adhesive layer by using the non-adhesive area is performed therein.