Abstract: A grease dispensing device includes a gun body, a push rod member, a driving unit, a linkage unit, and a connecting unit. The gun body has a barrel for receiving grease, and a dispensing tube member with an end portion connected to the barrel. The push rod member is inserted radially and slidably into the end portion of the dispensing tube member in order to push the grease out of the dispensing tube member when the push rod member is moved reciprocally. The driving unit has a rotatable output shaft. The linkage unit interconnects the rotatable output shaft of the driving unit and the push rod member for converting rotary motion of the output shaft into reciprocating motion of the push rod member. The connecting unit connects the driving unit and the gun body.