Abstract: An injection device made up from a housing, a dose setting and injection mechanism, a dose setting member and an injection button is described. The dose setting and injection mechanism is made as a preassembled unit insertable into the housing. Both the dose setting member and the injection button is thereafter connected to the preassembled dose setting and injection mechanism inside the boundaries of the housing, while being accessible for a user from outside the housing. The same preassembled dose setting and injection mechanism can fit into a large variety of different houses making production of different variants of an injection device somewhat easier.