An air compressor device comprising: a supporting base including a supporting plate and a cylinder housing, said cylinder housing including a chamber formed therein, and including an outlet receptacle extended upwardly from said cylinder housing for receiving a pressurized air from said chamber of said cylinder housing, said supporting plate including an orifice and an aperture formed therein, a piston slidably received in said chamber of said cylinder housing and having a piston rod extended from a piston head, a shaft rotatably engaged through said aperture of said supporting plate, a gear attached to said shaft and rotatable relative to said supporting plate, an eccentric member attached to said gear and including an eccentric pin extended from said eccentric member and coupled to said piston rod in order to actuate and move said piston head of said piston relative to said cylinder housing in a reciprocating action, a motor including a forwardly extended protrusion engaged into said orifice of said supporting plate, and including a spindle rotatably extended out of said protrusion and extended through said orifice of said supporting plate, and including a pinion attached to said spindle and meshed and engaged with said gear for allowing said gear to be driven by said motor with said pinion, and for allowing said piston head and said piston rod to be moved relative to said cylinder housing in the reciprocating action by said eccentric member and said eccentric pin, and said pinion including an outer diameter greater than an outer diameter (d) of said protrusion of said motor, characterized in that said supporting plate includes a plurality of teeth having a substantially trapezoidal cross-sectional shape, said teeth of said supporting plate being extended radially and inwardly into said orifice of said supporting plate for forming a plurality of slots between said teeth having a substantially trapezoidal cross-sectional shape, said teeth of said supporting plate include an addendum defined by the top surfaces of the teeth and a dedendum defined by the bottoms of slots, wherein the dedendum defines an inner diameter no less than the outer diameter of said pinion of said motor for allowing said pinion of said motor to be engaged through said orifice of said supporting plate, in that said protrusion of said motor includes an outer diameter (d) no greater than an inner diameter (a) defined by the addendum of said teeth of said supporting plate for allowing said protrusion of said motor to be engaged into said orifice of said supporting plate and engaged with said addendum of said teeth of said supporting plate, in that said motor includes a mounting seat on its outer diameter at its forward end and in that said supporting plate includes a protrusion placed on said mounting seat. a supporting base including a supporting plate and a cylinder housing, said cylinder housing including a chamber formed therein, and including an outlet receptacle extended upwardly from said cylinder housing for receiving a pressurized air from said chamber of said cylinder housing, said supporting plate including an orifice and an aperture formed therein, a piston slidably received in said chamber of said cylinder housing and having a piston rod extended from a piston head, a shaft rotatably engaged through said aperture of said supporting plate, a gear attached to said shaft and rotatable relative to said supporting plate, an eccentric member attached to said gear and including an eccentric pin extended from said eccentric member and coupled to said piston rod in order to actuate and move said piston head of said piston relative to said cylinder housing in a reciprocating action, a motor including a forwardly extended protrusion engaged into said orifice of said supporting plate, and including a spindle rotatably extended out of said protrusion and extended through said orifice of said supporting plate, and including a pinion attached to said spindle and meshed and engaged with said gear for allowing said gear to be driven by said motor with said pinion, and for allowing said piston head and said piston rod to be moved relative to said cylinder housing in the reciprocating action by said eccentric member and said eccentric pin, and said pinion including an outer diameter greater than an outer diameter (d) of said protrusion of said motor, characterized in that said supporting plate includes a plurality of teeth having a substantially trapezoidal cross-sectional shape, said teeth of said supporting plate being extended radially and inwardly into said orifice of said supporting plate for forming a plurality of slots between said teeth having a substantially trapezoidal cross-sectional shape, said teeth of said supporting plate include an addendum defined by the top surfaces of the teeth and a dedendum defined by the bottoms of slots, wherein the dedendum defines an inner diameter no less than the outer diameter of said pinion of said motor for allowing said pinion of said motor to be engaged through said orifice of said supporting plate, in that said protrusion of said motor includes an outer diameter (d) no greater than an inner diameter (a) defined by the addendum of said teeth of said supporting plate for allowing said protrusion of said motor to be engaged into said orifice of said supporting plate and engaged with said addendum of said teeth of said supporting plate, in that said motor includes a mounting seat on its outer diameter at its forward end and in that said supporting plate includes a protrusion placed on said mounting seat.