PatKaiser (警察合体 パトカイザー; "Keisatsu Gattai" translates to "Police Combination") is the main mecha of the Patranger team in the Japanese series Kaitou Sentai Lupinranger VS Keisatsu Sentai Patranger (2018–2019). The Patrangers are the show's police faction (Patren 1gou, 2gou and 3gou), set against the phantom-thief faction, the Lupinrangers. PatKaiser is therefore the police counterpart to the Lupinrangers' LupinKaiser. Because this season was never adapted into a Power Rangers series, there is no US name; the mecha is Japan-exclusive and was never released as a Power Rangers toy.

PatKaiser is assembled from the Patrangers' three Trigger Machines plus the sentient, talking support mecha GoodStriker, who alternately combines with either team over the course of the series. In the standard formation, Trigger Machine 1gou (the red patrol car) forms the chest and head, while Trigger Machines 2gou and 3gou become the arms – one arm serving as a gun/cannon, the other as a baton. Its signature finisher is the "PatKaiser Bullet Strike." The system is modular: additional Trigger Machines create further configurations such as PatKaiser Biker (with an oversized yo-yo ranged weapon), PatKaiser Strong (using Trigger Machine Crane and Drill), and PatKaiser Trains (using the X Train vehicles).

The DX toy was made by Bandai (Japan) and released in 2018 alongside the series' launch. The DX PatKaiser set includes GoodStriker along with Trigger Machines 1gou, 2gou and 3gou, which combine into the robot via transformation and connector mechanics. The figure is predominantly plastic (ABS/PVC); significant die-cast/metal content is not characteristic of this DX line. PatKaiser is part of this season's "VS Vehicles" toy system and is therefore compatible with additional, separately sold Trigger Machines to recreate the alternate formations (Biker, Strong, Trains, etc.). No Power Rangers version was ever produced.