Two case members of the same shape are attached to the body of an expansion valve and a temperature sensing drive element through sound insulating members. Each of the two case members is formed having upper retaining and retainable portions at its upper part and lower retaining and retainable portions at its lower part. The upper retaining portion, upper retainable portion, lower retaining portion, and lower retainable portion of one of the case members are in engagement with the upper retainable portion, upper retaining portion, lower retainable portion, and lower retaining portion, respectively, of the other case member.