A low cost portable dosing apparatus enables the dispensing rate to be changed while enabling solution to be continuously dispensed to the body. The solution to be dispensed into the body is stored in a tank unit. A pump unit pumps the solution from the tank unit into the body of the patient. A controller controls pump unit operation. The tank unit, pump unit, and controller are attached to a wrist strap so that they can be easily connected and disconnected from each other. A compact, thin ultrasonic motor with high output per unit size drives the pump unit. A smaller pump unit is thus available, improving the portability of the apparatus. The ultrasonic motor is also substantially free of misoperation resulting from exposure to magnetic fields because the ultrasonic motor is not magnetically driven. Reliability is therefore improved.