The horizontal contact resonance, which is formed by the resonant system due to the mass of a vibration pickup and the contact compliance of a setting point, causes errors in measurement and places restrictions on the measurement frequency range. The characteristics of the horizontal resonance depend on the type and condition of the ground surface and the method of planting the vibration pickup. This paper indicates the characteristics of the horizontal contact resonances of the rectangular vibration pickup with various base shapes, and derives expressions for a coupled motion of the pickup. It is suggested that the horizontal resonance and the response of the coupling system of the rectangular vibration pickup are significantly affected by the height of the center of gravity, the base area, and the base shape. The relationships are represented by a simple curve for the horizontal resonance. The agreements between the analog equations derived here and the values of the measurement on actual fields are well within the accuracy required for engineering analysis. The derived solutions provide adequate accuracy for practical applications to machine foundations with various rectangular bases.