Disclosed is to provide a design method and design system for a vehicular lamp, a program to execute designing of vehicular lamp and a record medium recording the program, which are capable of improving an efficiency of designing a lamp satisfying design conditions including performance conditions required as the vehicular lamp and restriction conditions given to each lamp. A vehicular lamp design system 1 includes: a database unit 2 having a standard database 21 registering standard data of a lamp and a technology database 22 registering technology data; and a lamp preparation unit 3 having a standard data selection part 31 and a morphing control part 32. The standard data selection part 31 generates design data by selecting standard data from the standard database 21 based on given design conditions. The morphing control part 32 updates a necessary part of the design data by use of the technology data of the technology database 22.