Abstract: An injection timing measuring method and device require a reduced amount of time for calculation. A reference position signal is generated at a predetermined crank angle within the range of 30.degree. CA to 90.degree. CA prior to TDC. Crank angle signals from a crank angle sensor are used as main measuring increments to measure a period starting from generation of the reference position signal and ending upon generation of an injection signal by a lift sensor provided in an injection valve unit, and another period starting from generation of the reference position signal and ending upon generation of a TDC signal. The injection timing relative to the TDC is provided as a difference between the two periods. Each period is precisely measured by counting crank angle signals generated within the period and by determining the remaining duration from the last-counted signal to generation of the injection or TDC signal as a fraction of the crank angle signal interval.