Part-time job

I start working in a japanese factory since 2 months ago.
I made contract of 3 months with them.
I work from 8am to 6pm, but last week we had few things to do so they send us home earlier than our working time.
As i am payed per hour, i am wondering if finnishing work earlier means i will be payed less because i worked some hours less.

Please help with

Read your work contract.

This is Full time job,not part time.As a student I worked 28 hours per week.So how you can worked 10 hours per Day.

By Jo,

Not true.
A part-time contract is max 28 hours, but often people work 40 hours on this contract.
This often happens in factories and English teaching jobs.

If there is less work you can leave and dont get paid.
Also often companies dont need to arrange pension and social health care.

So OP needs to confirm the contract if it is part-time or fulltime.