To provide a syringe pump capable of efficiently sensing an obstruction to an actuator for driving a syringe.

The syringe pump has a motor 9 for rotating a leadscrew 8 to drive a plunger head actuator 10 along this leadscrew. The actuator 10 engages the plunger 35 of a syringe 3 and moves the plunger along the syringe barrel to dispense medication. An optical encoder 20 mounted on the leadscrew 8 is rotated by the motor 9 to output a pulse signal. A control unit 11 times the interval between the pulses and compares these timings with a stored value which is a representative of a predetermined multiple of the minimum time. If the actuator 10 is obstructed, the speed of rotation of the motor 9 is slowed and the interval between the pulses is increased. If the pulse interval exceeds the stored value, the unit 11 stops the drive of the actuator 10 and generates an alarm.