This study proposes a facile method for preparing microfluidic devices applicable to middle and high school lab class. Instead of using elastomers such as PDMS, we propose to use edible materials such as gelatin to alleviate safety concerns, reduce cost, and shorten fabrication time. The device molds were produced using a 3D printer, which is affordable for educational institutions. The observation of laminar flow using the fabricated device was demonstrated to be feasible not only with a lab-level optical microscope but also with a smartphone. The proposed method has the potential to enhance the understanding of fluid dynamics such as laminar flow in class.