Fuel pressure controller for internal combustion engine

A fuel pressure controller includes processing circuitry that executes a first process, a second process, and a third process as a fuel pressure reduction control. The first process includes closing both a first electromagnetic valve and a second electromagnetic valve. The second process includes adjusting the pressure of the fuel supplied to a fuel injection valve by repeatedly performing an opening and closing operation of the second electromagnetic valve. The third process includes, when the fuel pressure in a fuel pipe between the first electromagnetic valve and the second electromagnetic valve reaches a prescribed pressure, stopping the opening and closing operation of the second electromagnetic valve to maintain the second electromagnetic valve in an open state, and repeatedly performing the opening and closing operation of the first electromagnetic valve to adjust the pressure of the fuel supplied to the fuel injection valve.