The utility model relates to a fan structure, in particular to a window-type fresh air machine. The window-type fresh air machine can continuously provide fresh air. According to the technical scheme, the window-type fresh air machine comprises an air pipe, one end of the air pipe is provided with an air pipe air inlet, the air pipe air inlet is communicated with a pipe cavity in the air pipe, the outer wall of the other end of the air pipe is fixedly provided with a fan, an air inlet of the fan is communicated with the pipe cavity of the air pipe, filtering cotton and a filtering film are arranged between the air inlet of the fan and the air pipe air inlet, and the filtering cotton and the filtering film are located in the air pipe and matched with the pipe cavity of the air pipe. The two ends of the air pipe are provided with the air pipe air inlet and the fan respectively, the filtering cotton and the filtering film in the air pipe filter air entering the air pipe air inlet, and accordingly the fresh air can be continuously provided from an air outlet of the fan. The window-type fresh air machine is simple and compact in structure, convenient to install, low in cost, wide in application range, safe and reliable.