We propose and implement methods for making collaborative searches more efficient in mobile computing environments. In mobile collaborative searches, the small screens of mobile devices make it difficult to share information such as discovered Web pages, evaluations of these, and information related to their search topics. We propose and implement a system supporting mobile collaborative searches, which provides a function for informing others about Web pages by inserting them into others' search results using simple actions; a function of displaying information related to others' search topics; and a function of showing the most positively evaluated Web pages at the top of the list of discovered Web pages. We also propose a method for the system to create a group of mobile devices easily. The results of evaluation tests show these methods support the sharing of information and improve the users' satisfaction.