This research aims to produce a learning media by using a valid, practical, and effective guided inquiry model to improve elementary school student’s critical thinking skill on the subject of force and motion. The development method is conducted by using 4-D model design, consisting: (1) defining, (2) designing, (3) developing, (4) distributing. Data is collected by using method of: validation, observation, test, and questionnaire. Then, data is analyzed to reveal the validity of the learning media based on the quality of: syllable, lesson plan, student textbook, student activity sheet, and critical thinking skill text by using a validation sheet. To reveal the practicality of the learning media, an observation sheet of the learning implementation and student activity is used. And to reveal the effectiveness of the learning media, an instrument of critical thinking skill text and a student response sheet is used. Results of the research show that : (1) the learning media is said to be valid and reliable, (2) the implementation  of lesson plan and student activity is said to be practical, good as well as effective.