A wafer-type tumbler cylinder comprises a sleeve, a cylinder, some wafers, and some springs. A shaft of the cylinder includes a first and a second semicircular columnar body. The first semicircular columnar body includes a front flanges, a rear drive section and a U-shaped indentation at the inner lateral surface that provides for insertion into the second semicircular columnar body. On the first and second semicircular columnar bodies, one or more slots are disposed to fasten with the wafers. A relatively wider rectangular notch is disposed between the inner sides of every two slots, which are respectively installed with a wafer; only one spring is positioned in the wider rectangular notch, thereby serving as a shared spring for every two wafers. The material cost of a spring is saved; besides, it's able to prevent from prying effectively because a burglar cannot pry two wafers supported by a shared spring.