A numerical controller includes a look-ahead unit configured to look ahead a block in the program into a buffer, a remaining block determination unit configured to determine whether retraction of a tool is needed or return of the tool is needed based on an amount of the block looked ahead in the buffer, a tool operation control unit configured to control retraction and return of the tool when the remaining block determination unit determines that retraction of the tool is needed, a block division unit configured to divide a block to divide at a position apart from both ends of the block according to a command from the tool operation control unit, and a tool path generation unit configured to generate a tool retraction path and a tool return path and insert the generated paths into a divided position in the block divided by the block division unit.