A data collecting device configured to communicate with a system including electronic control units (101 to 107) controlling various functions (A to E) to collect function data (Da to De) about the functions (A to E), said data collecting device comprising: a list information generating section which is configured to, before starting to collect function data (Da to De), communicate with all the electronic control units (101 to 107) in the system to recognize the functions (A to E) controlled by the electronic control units (101 to 107) and to generate unit-specific function list information (LD1, LD2) which is a list of the functions (A to E) categorized by function type and by electronic control unit (101 to 107); a function selecting section which is configured to select at least one function type (A to E) about which function data (Da to De) is to be collected; and a data collecting section which is configured to communicate by using at least one of the electronic control units (101 to 107) which corresponds to the at least one function (A to E) selected by the function selecting section as at least one communication address on the basis of the unit-specific function list information (LD1, LD2) generated by the list information generating section to collect function data (Da to De) about the at least one function (A to E) corresponding to the selection information, wherein at least one of the functions (A to E) is controlled distributively by two or more of the electronic control units (101 to 107) in the system and is designated as a common function for at least two of the electronic control units (101 to 107), and wherein a designated representative electronic control unit (101 to 107) which is either one of the two or more of the electronic control units (101 to 107) is configured to communicate with the other electronic control unit (101 to 107) of the two or more of the electronic control units (101 to 107) to obtain common function data (Da to De) about the common function (A to E), and wherein the list information generating section is configured to generate the unit-specific function list information (LD1, LD2) containing information on the representative electronic control unit (101 to 107), and wherein the data collecting section is configured, in response to the common function (A to E) selected through the function selecting section, to communicate by using the representative electronic control unit (101 to 107) as a communication address on the basis of the unit-specific function list information (LD1, LD2) containing information on the representative electronic control unit (101 to 107) to collect the common function data about the common function (A to E) corresponding to the selection information. a list information generating section which is configured to, before starting to collect function data (Da to De), communicate with all the electronic control units (101 to 107) in the system to recognize the functions (A to E) controlled by the electronic control units (101 to 107) and to generate unit-specific function list information (LD1, LD2) which is a list of the functions (A to E) categorized by function type and by electronic control unit (101 to 107); a function selecting section which is configured to select at least one function type (A to E) about which function data (Da to De) is to be collected; and a data collecting section which is configured to communicate by using at least one of the electronic control units (101 to 107) which corresponds to the at least one function (A to E) selected by the function selecting section as at least one communication address on the basis of the unit-specific function list information (LD1, LD2) generated by the list information generating section to collect function data (Da to De) about the at least one function (A to E) corresponding to the selection information, wherein at least one of the functions (A to E) is controlled distributively by two or more of the electronic control units (101 to 107) in the system and is designated as a common function for at least two of the electronic control units (101 to 107), and wherein a designated representative electronic control unit (101 to 107) which is either one of the two or more of the electronic control units (101 to 107) is configured to communicate with the other electronic control unit (101 to 107) of the two or more of the electronic control units (101 to 107) to obtain common function data (Da to De) about the common function (A to E), and wherein the list information generating section is configured to generate the unit-specific function list information (LD1, LD2) containing information on the representative electronic control unit (101 to 107), and wherein the data collecting section is configured, in response to the common function (A to E) selected through the function selecting section, to communicate by using the representative electronic control unit (101 to 107) as a communication address on the basis of the unit-specific function list information (LD1, LD2) containing information on the representative electronic control unit (101 to 107) to collect the common function data about the common function (A to E) corresponding to the selection information.