The probability of a cancer patient being cured depends largely on the stage of disease at the time of diagnosis. It is therefore very important to develop methods for early cancer diagnosis that would allow screening of a large number of samples in a short time. Here, a unique method is presented for rapid immunodetection of heat shock proteins (HSPs). The method uses a compact acoustic sensor based on a lateral-field piezoelectric resonator and specific phage antibodies. The phage antibodies for the first time were developed against HSPs of P3X63Ag8.653 mouse myeloma cells. The change in the electric impedance modulus of resonator after recording of phage antibody–HSP interaction served as the analytic signal with analysis time less than 5 min. Antibody-HSP interaction confirmed by microscopic analysis and flow cytometry. This study establishes a new strategy for early cancer diagnosis by compact acoustic sensor with phage antibodies as sensing element. The results can be used to develop a noninvasive rapid method of early cancer diagnosis on basis of HSP determination and to control the content of HSPs in the monitoring of tumor therapy.