[Problems]To provide a variable phase controller for an engine which assures easy manufacturing at low cost, reduces operating sound, and includes a relative rotational motion mechanism enabling quick change of a phase angle between a cam shaft and a crank shaft.[Means for Solving Problems]A variable phase controller for an engine controls the rotational motion of a first control rotor for changing the relative phase angle between a crank shaft and a cam shaft to either a phase-lead angle side or a phase-lag angle side in accordance with the direction of such control. The variable phase controller has a first braking means for rotating the first control rotor to one side, and a second braking means for braking a second control rotor and rotating the first control rotor in the direction opposite to the rotation caused by the first braking means via a second intermediate rotor (or cam guide plate) displaced by the force applied by a movable element (or rotating eccentric circular cam) displaced in guide grooves by braking of the second control rotor, thereby controlling the rotational motion of the first control rotor.