A drive controller that controls a drive of a motor. The drive controller performs a collision force moderation control during a motor start time, during which a collision force in a collision between a shaft outwall with an impeller hole inwall for a positioning is moderated, by changing a power supply at a stage transition time of transiting from a position detection to a position determination. The maximum value of a first output value during a position detection time is set to be greater than a first threshold that at least causes a rotation number of the motor to yield a detectable induction voltage. A second output value during a position determination time is set to be lower than a second threshold that causes a wear or a breakage of an impeller by the collision force.