A method of manufacturing a surface mount type crystal oscillator having a container body including a first recess and a second recess respectively formed in two main surfaces thereof, a crystal blank hermetically sealed in the first recess, an IC chip having an oscillation circuit integrated thereon and secured to the bottom surface of the second recess through thermo-compression bonding using bumps, and a protection resin for protecting a circuit-forming surface of the IC chip comprises the steps of applying a protection resin consisting of a flexible resin along the inner periphery of the second recess, and pressing the IC chip while the outer periphery of the IC chip is brought into contact with the applied protection resin to secure the IC chip to the bottom surface of the second recess.