A control device for a hybrid vehicle for switching among a plurality of travel modes including a series mode in which drive wheels (16, 19) are driven by power of an electric motor (9, 11) driven by electric power generated by a power generator driven by power of an internal combustion engine mounted on the vehicle, and a parallel mode in which the drive wheels are driven by power of the internal combustion engine and power of the electric motor driven by electric power supplied from a secondary battery mounted on the vehicle, comprising: a plurality of sensors (4a, 4c, 4d, 4e) that detect an operation state of the internal combustion engine; hybrid control means including a mode switching portion for switching among the plurality of travel modes depending on a traveling state of the vehicle, and an output value control portion for calculating an output value of the internal combustion engine in the series mode and the parallel mode; and internal combustion engine control means for controlling operation of the internal combustion engine based on detection values from the plurality of sensors and the output value calculated by the output value control portion, whereby the internal combustion engine control means has abnormality determination information set for each abnormality in each of the plurality of sensors (4a, 4c, 4d, 4e) based on a degree of influence of the abnormality in each of the plurality of sensors on traveling of the vehicle, and, when an abnormality is detected in any of the plurality of sensors, the internal combustion engine control means sends, to the hybrid control means, the abnormality determination information corresponding to the sensor in which the abnormality has been detected, characterized in that the hybrid control means is configured to prohibit the parallel mode and switch the travel mode to the series mode if the abnormality determination information received from the internal combustion engine control means is based on a first degree of influence as the degree of influence on travelling of the vehicle, and to prohibit the parallel mode and switch the travel mode to the series mode in which the output of the internal combustion engine is limited, if the abnormality determination information received from the internal combustion engine control means is based on a second degree of influence higher than the first degree of influence, as the degree of influence on traveling of the vehicle. a plurality of sensors (4a, 4c, 4d, 4e) that detect an operation state of the internal combustion engine; hybrid control means including a mode switching portion for switching among the plurality of travel modes depending on a traveling state of the vehicle, and an output value control portion for calculating an output value of the internal combustion engine in the series mode and the parallel mode; and internal combustion engine control means for controlling operation of the internal combustion engine based on detection values from the plurality of sensors and the output value calculated by the output value control portion, whereby the internal combustion engine control means has abnormality determination information set for each abnormality in each of the plurality of sensors (4a, 4c, 4d, 4e) based on a degree of influence of the abnormality in each of the plurality of sensors on traveling of the vehicle, and, when an abnormality is detected in any of the plurality of sensors, the internal combustion engine control means sends, to the hybrid control means, the abnormality determination information corresponding to the sensor in which the abnormality has been detected, characterized in that the hybrid control means is configured to prohibit the parallel mode and switch the travel mode to the series mode if the abnormality determination information received from the internal combustion engine control means is based on a first degree of influence as the degree of influence on travelling of the vehicle, and to prohibit the parallel mode and switch the travel mode to the series mode in which the output of the internal combustion engine is limited, if the abnormality determination information received from the internal combustion engine control means is based on a second degree of influence higher than the first degree of influence, as the degree of influence on traveling of the vehicle.