A miniature zoom lens has, sequentially from an object side, a first lens group G1 having negative refractive power, a second lens group G2 having positive refractive power and including a diaphragm, and a third lens group G3 having positive refractive power. The first lens group G1 is formed from a single negative lens L1. The second lens group G2 is formed from, sequentially from the object side, a single positive lens L2 and a single negative lens L3. The third lens group G3 is formed form a single positive lens L4. The first lens group G1 is immovable and the second lens group G2 and the third lens group G3 move in an optical axis direction at variable power. The miniature zoom lens provides a large zoom ratio while keeping a constant total length.