The conventional endoscopes generate pains and discomfort to patients due to the stiffness of their body and cannot reach to small intestines. Therefore, the wireless capsule-type endoscope, M2A, has been developed. However, commercialized capsule-type endoscopes move passively by peristaltic waves (and the gravity), which has limitation for doctors to diagnose more thoroughly and actively. In order to solve this problem, a locomotive mechanism is proposed for wireless capsule-type endoscopes. Based on the tests of various actuators, spring-type SMA actuators are selected as micro actuators for capsule endoscopes. Thus, two-way linear actuators using a pair of SMA springs are developed based on a static analysis on them. Moreover, a simple and effective clamping device is developed based on biomimetic approach. A prototype endoscope with four pairs of SMA springs and four clampers was developed. It is 13 mm in diameter and 33mm in total length, with a hollow space of 7.6 mm in diameter to comprise endoscope components such as a camera, and communication module, sensors, and a battery. A sequential control of the four actuation modules improves the efficiency of locomotion up to four times. For feasibility test of proposed locomotive mechanism, a series of experiments were carried out including in-vitro tests. Based on results of the experiments, we conclude that the proposed locomotive mechanism is effective to be used for micro capsule-type endoscopes