Portable measuring instrument

The utility model specifically relates to a portable measuring instrument, and belongs to the technical field of vector network analysis equipment. The portable measuring instrument comprises a main shell, two plugging parts and a mounting frame, the main shell comprises four surface walls connected in sequence, the four surface walls define a channel extending in the first direction, the four surface walls comprise the first wall and the third wall which are opposite in the second direction, heat dissipation holes are formed in at least one of the first wall and the third wall, the first direction is perpendicular to the second direction, and the two blocking parts are used for blocking two ports of the channel respectively. The mounting frame is connected to one of the two plugging parts, the mounting frame is contained in the main shell, and a cooling fan is arranged on at least one of the two sides of the mounting frame in the second direction. And the mounting frame is taken out of the main shell or sent