A control device for a high pressure fuel pump (33) for fuel injection (14) in which values of at least seven parameters of an engine speed, an engine load, a lubrication oil temperature, an amount of fuel supplied to the high pressure fuel pump (33), a temperature of intake air fed into the engine, a temperature of fuel discharged from the high pressure fuel pump (33), and a vehicle speed are acquired, and a learned neural network learned in weights using acquired values of the seven parameters as input values of the neural network and using as training data the temperature of fuel discharged from the high pressure fuel pump (33) acquired after a fixed time period from when acquiring the values of the seven parameters is stored, At the time of an engine operation, the temperature of fuel discharged from the high pressure fuel pump (33) after the fixed time period is estimated by using the learned neural network from the current estimated temperature of fuel discharged from the high pressure fuel pump (33).