Provided is a piston push rod assembly which can prevent discomfort from being imparted during the operation of a brake pedal by a driver. In the piston push rod assembly, a second piston (1b) is provided with a piston slide section (1b1) which is housed in a cylinder and which slides relative to the cylinder, and a connection tube section (1b2) which is connected to a push rod (R); the piston slide section (1b1) is covered by metal plating; the connection tube section (1b2) has a non-plated section; and the second piston (1b) and the push rod (R) are connected by the caulking of the connection tube section (1b2) when the push rod (R) has been inserted inside the connection tube section (1b2).