A desktop computer has a base, a front case, a display panel, a motherboard, a device frame, and a rear case. The front case has a front panel, an upper panel and a lower panel. The display panel is positioned on the front side of the front panel and electrically connected to the motherboard positioned on the rear side of the front panel. The device frame is employed to fix a peripheral device electrically connected to the motherboard. The upper side and the lower side of the device frame are respectively in contact with the inner sides of the upper panel and the lower panel of the front case to form a supporting frame on the rear side of the front case. The rear case is positioned on the rear side of the front case and employed to cover the motherboard and the device frame.