PURPOSE: To prevent erroneous fail judgment by carrying out fail judgment for stopping feedback control of a fuel pressure in the case where a measured value of an advance angle quantity at a fuel injection timing is different from a target value while inhibiting the fail judgment in the case of a low fuel temperature.

CONSTITUTION: Upon energization to an electromagnetic coil of a timing control valve 45, a high pressure chamber 43 of a timer cylinder 37 is communicated with a low pressure chamber 41 thereof, thus reducing a fuel pressure at the high pressure chamber 43. As a result, a timer piston 38 is moved, by energizing force of a spring 40, to a position where a pressure at the high pressure chamber 43 is balanced, whereby a fuel injection timing is changed. A control circuit 55 controls the valve 45 on the basis of signals detected by a fuel temperature sensor 35, a load sensor 56, and a position sensor 54. If a measured value of a position of the piston 38 is different from a target value, a fail judgment for stopping feedback control is carried out. Meanwhile, in the case where a fuel temperature is low, a fail judgment at the time of clogging of a filter is inhibited.