A semiconductor device with a novel structure is provided. The semiconductor device includes a plurality of arithmetic blocks each including an arithmetic circuit portion and a memory circuit portion. The arithmetic circuit portion and the memory circuit portion are electrically connected to each other. The arithmetic circuit portion and the memory circuit portion have an overlap region. The arithmetic circuit portion includes, for example, a Si transistor, and the memory circuit portion includes, for example, an OS transistor. The arithmetic circuit portion has a function of performing product-sum operation. The memory circuit portion has a function of retaining weight data. A first driver circuit has a function of writing the weight data to the memory circuit portion. The weight data is written to all the memory circuit portions included in the same column with the use of the first driver circuit.