Provided is a memory structure including a substrate having a memory region and a peripheral region, a capacitor array, a transistor array, bit lines, and contacts. The capacitor array is on the substrate in the memory region. The transistor array is on and electrically connected to the capacitor array. The bit lines are extended along a row direction in parallel with each other on the transistor array, and are electrically connected to the transistor array. Each of the contacts is connected to one of the bit lines and a conductive device at the substrate in the peripheral region. Each of the contacts includes a first portion, a second portion, and a third portion. The second portion is between the first portion and the third portion. The third portion is electrically connected to the conductive device. Distances between each of the third portions and the memory region are the same.