The pump is made on the basis of circulating water multi purpose vacuum pump, and in view of the small space of the lab, and with reference to the Japan -made bench-type pump, made with reduced size and improvement, and adopting one-shot forming, it has the feature of small size, light weight and beautiful appearance and so on, it has double-size-double- tap air extracting, 4-size-4-tap , identical dual size multi purpose vacuum pump. While the teacher is demonstrating, students can also turning on or off the machine on any size of it. 1. It adopts dual taps, can be used independently or in parallel combination, with 2 vacuum meters. 2. Newly improved anticorrosion four taps can be used independently or in parallel combination, with 4 vacuum meters. 3. The host machine has two models; one is made with stainless steel module and the other with anticorrosion materials. 4. It is corrosion resistant, pollution free and with low noise, and easy to move, also, vacuum-adjusting valve can be added according to the needs of customers. 5. Four students can conduct chemical experiments simultaneously, reducing experiment space.