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We analyzed the Kepler long cadence data of KIC 7524178 (=KISJ192254.92+430905.4), and found that it is an SU UMa-type dwarf nova withfrequent normal outbursts. The signal of the negative superhump was always thedominant one even during the superoutburst, in contrast to our common knowledgeabout superhumps in dwarf novae. The signal of the positive superhump was onlytransiently seen during the superoutburst, and it quickly decayed after thesuperoutburst. The frequency variation of the negative superhump was similar tothe two previously studied dwarf novae in the Kepler field, V1504 Cyg and V344Lyr. This is the first object in which the negative superhumps dominatethroughout the supercycle. Nevertheless, the superoutburst was faithfullyaccompanied by the positive superhump, indicating that the tidal eccentricinstability is essential for triggering a superoutburst. All the pieces ofevidence strengthen the thermal-tidal instability as the origin of thesuperoutburst and supercycle, making this object the third such example in theKepler field. This object had unusually small (~1.0 mag) outburst amplitude andwe discussed that the object has a high mass-transfer rate close to the thermalstability limit of the accretion disk. The periods of the negative and positivesuperhumps, and that of the candidate orbital period were 0.07288 d (average,variable in the range 0.0723-0.0731 d), 0.0785 d (average, variable in therange 0.0772-0.0788 d) and 0.074606(1) d, respectively.

KIC 7524178 -- an SU UMa-Type Dwarf Nova Showing Predominantly Negative Superhumps throughout Supercycle