A cascode crystal oscillator is widely used for the stable frequency source of mobile communication equipments. Recently, IC production of the cascode crystal oscillator has become necessary. The cascode crystal oscillator is composed of a colpitts crystal oscillator and a cascode connected base-common buffer amplifier. The base bypass condenser prevents the area size reduction. In this paper, we have proposed the new structures of the cascode crystal oscillator suitable for integrated circuits. The proposed circuits have the advantages on reduction of the area size and start-up time without deteriorating the frequency stability against the load impedance variation and other performances. The simulation and experiment have shown the effectiveness of the proposed circuits.