I use two different patents owned by others to reassemble a new device. Can I apply for a patent for the new device? Is it an infringement?

It is an infringement. If you apply for a patent, it is a combination patent and can be applied for, but it is not necessarily authorized. There is a possibility of authorization. Even if you apply for a patent on a new device, the product you manufacture still infringes on the first two patents. Just because you apply for a patent does not infringe on someone else's patent. These are two independent acts.