To provide a mode transition control device of a hybrid car capable of preventing driving force shocks in a mode transition period in which engagement elements are engaged or disengaged while achieving the mode transition with excellent response when selecting a mode of a fixed gear ratio.

The mode transition control device of the hybrid car comprises a power source by an engine 1 and two motor generators MG1 and MG2, a planetary gear transmission having engagement elements capable of obtaining the fixed gear ratio by the engagement from a state of a continuously variable speed change function by disengagement, a mode selection means to select a drive mode, a gear ratio control means to control the gear ratio by the closed loop control based on the operating point command of each power source, and an engagement element control means to control the engagement/disengagement of the engagement elements. A driving force shock preventive control means to reduce the control gain of at least one of the gear ratio control means and the engagement element control means in the engagement area and the disengagement area of the engagement elements when the fixed gear ratio mode is selected by the mode selection means is provided.

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