A digital smart security system comprising: a first communication terminal worn on a user and comprising: (i) respiratory information acquiring means for acquiring respiratory information from a respiration sensor for detecting breathing of the user to which the respiratory sensor is fitted; (ii) abnormality determining means for determining whether it is an abnormality, based on the respiratory information, depending on whether breathing stops for a predetermined period of time and resumes; control means (110,200,201) for reporting an abnormal situation in response to the abnormality determining means having determined that it is an abnormal situation, wherein the abnormality determining means is configured to determine that it is a security abnormality, based on the respiratory information, if breathing stops for a predetermined period of time and resumes, and to determine that it is a health abnormality of the user, if breathing stops and doesn't resume, and wherein the control means is configured to make different reports depending on the security abnormality and the health abnormality; positional information acquiring means for detecting existing positions of a plurality of further communication terminals, and acquiring positional information of the first communication terminal; and jurisdiction retaining means for retaining a jurisdictional district for receiving an emergency telephone call where a building under security exists, wherein the control means is configured to refer to the jurisdiction retaining means based on the positional information of the first communication terminal in response to the abnormality determining means having determined that it is an abnormal situation, and if any of the plurality of the further communication terminals exists in the jurisdictional district, to report preferentially to the further communication terminal existing in the jurisdictional district. a first communication terminal worn on a user and comprising: (i) respiratory information acquiring means for acquiring respiratory information from a respiration sensor for detecting breathing of the user to which the respiratory sensor is fitted; (ii) abnormality determining means for determining whether it is an abnormality, based on the respiratory information, depending on whether breathing stops for a predetermined period of time and resumes; (i) respiratory information acquiring means for acquiring respiratory information from a respiration sensor for detecting breathing of the user to which the respiratory sensor is fitted; (ii) abnormality determining means for determining whether it is an abnormality, based on the respiratory information, depending on whether breathing stops for a predetermined period of time and resumes; control means (110,200,201) for reporting an abnormal situation in response to the abnormality determining means having determined that it is an abnormal situation, wherein the abnormality determining means is configured to determine that it is a security abnormality, based on the respiratory information, if breathing stops for a predetermined period of time and resumes, and to determine that it is a health abnormality of the user, if breathing stops and doesn't resume, and wherein the control means is configured to make different reports depending on the security abnormality and the health abnormality; positional information acquiring means for detecting existing positions of a plurality of further communication terminals, and acquiring positional information of the first communication terminal; and jurisdiction retaining means for retaining a jurisdictional district for receiving an emergency telephone call where a building under security exists, wherein the control means is configured to refer to the jurisdiction retaining means based on the positional information of the first communication terminal in response to the abnormality determining means having determined that it is an abnormal situation, and if any of the plurality of the further communication terminals exists in the jurisdictional district, to report preferentially to the further communication terminal existing in the jurisdictional district.