A mobile station comprising: a degradation detecting section (15, 26) for detecting a degraded communication quality of the mobile station; an electric field measurement section (14, 25) for measuring an intensity of an electric field of the mobile station; and a display section (16, 27) for representing an electric field level among a plurality of electric field levels, characterized by: a control section (13, 24) for allowing the display section (16, 27), when the degradation detecting section (15, 26) detects no degraded communication quality, to represent a first electric field level among the plurality of electric field levels corresponding to said measured intensity of the electric field and, when the degradation detecting section (15, 26) detects the degraded communication quality, to represent a second electric field level among the plurality of electric field levels that is fixed regardless of said measured intensity of the electric field, and wherein said degradation detecting section (15, 26) and said field level measurement section (14, 25) are adapted to periodically detect a degradation of a communication quality and measure said intensity of said electric field, respectively, at respective time intervals, further comprising a movement detector (31; 24) for detecting a movement of said mobile station, wherein said degradation detecting section is adapted to detect said degradation of said communication quality at a longer time interval upon detection of a stationary state of said mobile station by said movement detector (31; 24). a degradation detecting section (15, 26) for detecting a degraded communication quality of the mobile station; an electric field measurement section (14, 25) for measuring an intensity of an electric field of the mobile station; and a display section (16, 27) for representing an electric field level among a plurality of electric field levels, characterized by: a control section (13, 24) for allowing the display section (16, 27), when the degradation detecting section (15, 26) detects no degraded communication quality, to represent a first electric field level among the plurality of electric field levels corresponding to said measured intensity of the electric field and, when the degradation detecting section (15, 26) detects the degraded communication quality, to represent a second electric field level among the plurality of electric field levels that is fixed regardless of said measured intensity of the electric field, and wherein said degradation detecting section (15, 26) and said field level measurement section (14, 25) are adapted to periodically detect a degradation of a communication quality and measure said intensity of said electric field, respectively, at respective time intervals, further comprising a movement detector (31; 24) for detecting a movement of said mobile station, wherein said degradation detecting section is adapted to detect said degradation of said communication quality at a longer time interval upon detection of a stationary state of said mobile station by said movement detector (31; 24). a control section (13, 24) for allowing the display section (16, 27), when the degradation detecting section (15, 26) detects no degraded communication quality, to represent a first electric field level among the plurality of electric field levels corresponding to said measured intensity of the electric field and, when the degradation detecting section (15, 26) detects the degraded communication quality, to represent a second electric field level among the plurality of electric field levels that is fixed regardless of said measured intensity of the electric field, and wherein said degradation detecting section (15, 26) and said field level measurement section (14, 25) are adapted to periodically detect a degradation of a communication quality and measure said intensity of said electric field, respectively, at respective time intervals, further comprising a movement detector (31; 24) for detecting a movement of said mobile station, wherein said degradation detecting section is adapted to detect said degradation of said communication quality at a longer time interval upon detection of a stationary state of said mobile station by said movement detector (31; 24).