Ultrasonic sensor (1) includes piezoelectric element (7), first acoustic matching layer (2), and second acoustic matching layer (5) which are laminated and bonded together, piezoelectric element (7) having a rectangular bonding surface. First acoustic matching layer (2), which is adjacent to piezoelectric element (7), is bonded to piezoelectric element (7) using thermoplastic resin injected from a thickness direction of first acoustic matching layer (2) in a manner that a flow direction of the thermoplastic resin matches a longitudinal direction of piezoelectric element (7). With this configuration, ultrasonic sensor (1) that exhibits excellent temperature characteristics against such as thermal shock is provided.