To provide a tandem type oil pump for merging after being straightened, without collision of lubricating oil delivered from both pumps.

This tandem type oil pump has a spacer 3 between a first trochoidal pump 4 and a second trochoidal pump 5 inside of a housing body 1. The spacer 3 is provided with a partition part 33b for partitioning delivery ports 31b and 32b on both sides in the shaft direction, and merges the lubricating oil delivered from the delivery ports 31b and 32b on the downstream side of the partition part 33b.