This study aims to produce STAD type cooperative learning tools that are well categorized so as to improve student learning outcomes of class VII in rectangular material. Type of research used is research development. Learning device development model used is 4-D model. The development process consists of four stages including definition, planning, development and dissemination. The results of the development of the device in the form of learning implementation plan (RPP), Student Worksheet (LKS), and Tests of Learning Results (THB). Based on the experimental result of the device, the STAD cooperative learning learning tools are valid by validator and fulfill the requirements: (1) valid learning test, reliable, and sensitive, (2) teachers' ability in managing good learning, (3) student activity in effective learning, (4) positive student response, and (5) mastery learning is classically met. Furthermore, based on the results of descriptive statistic analysis, it is found that the learning model of STAD is effective to teach rectangular material because the learning effectiveness requirements are fulfilled, namely: (1) the ability of the teacher to manage the learning well, (2) the student activity in effective learning, (3) the response students to positive learning, (4) mastery learning is classically met. Based on inferential statistic analysis using ANAKOVA, it is concluded that the learning result of experiment class students using STAD type cooperative learning is better than control class students using conventional learning.